A GREAT book about a generation ship experiencing a similar scenario to the one you talked about is Aurora by Kim Stanley Robinson. That book convinced me that generation ships are one of the most morally awful things we could do. Great read, do recommend
Another book that explores this in a very reasonable way is The Three Body Problem. I don't want to spoil too much but interstellar travel is portrayed only in terms of generational ships and it is NOT GOOD. Every ship has to be its own fascist nightmare to keep people from rebelling. But the book has this exciting quality because at multiple times in its story, there's a compelling reason for a civilization to embark on a hundreds or thousands-years long journey, and they just do it.
This book also has some things Jason would call magical, but its portrayal to interstellar travel is nothing a nerd would fantasize about.
In The Three Body Problem, the interstellar travelers had suspended animation built into their physiology, and they knew their planet was a death trap. The time scale is right, though.
Well for others reading, you've been warned about a big fat SPOILER:
At one point, a few ship's worth of humans barely escape earth and have to form a society en route to a start that's some crazy distance away, hundreds of years, and it's just to refuel. The author does an amazing job of describing how impossibly lonely and dehumanizing space is, like they all lose there innocence at once. There's a brief Mexican standoff over parts, one ship wins, and off they go, as cold, hardened, fascist murderers. It's wild. I highly recommend the whole trilogy, except the first third of book two which could've been a chapter.
Stephenson dealt with it in Seveneves by first rendering Earth uninhabitable for many generations, leaving the space colonies the only way to preserve humanity. But it devolved into mawkish feminist nonsense along the way - women as the literal saviors of humanity because of their superior ways. Not his best book, by far.
Some of the best new country music I hear lately is coming from Shaboozey, Darius Rucker and similar. Same tropes but better melodies. Mostly I listen to country from the 80/90s when I was young and tooling around the western Carolinas in my stick shift ranger.
I’m reading The Mountain in the Sea by Ray Nayler. The first third has me neglecting my clients in favor of reading. Anyone know of similar authors? Or new material in the same vein as Corey or early Stephenson?
And if you're still not satisfied, may I suggest The Overstory? That's my final offer. Unfortunately I'm not a scifi aficionado, but I think this is your style...
You should give his “Polostan” a try. It’s more historical fiction than sci-fi. If you read/like his Baroque Cycle books, this is in the same vein although written in modern language/style.
KSR seems to have soured on the peak technological optimism of his Mars trilogy, where "the treatment" extended lifespans by a factor of 3 or 4x. _2312_ posited mysterious problems with long-term life off Earth, and _Aurora_ took this skepticism even further by making the ships ultimately incapable of being a generational human habitat.
IMHO the major failure of the Aurora mission wasn't the ship itself, it was largely intact and functional when it got to Tau Ceti. The problem was the survey of Tau Ceti was incomplete and failed to account for the environmental problems there. The division and reduction of ship resources seemed to be a bigger problem on the return voyage than the ship itself.
I'm not sold on the moral problems of future generations being born on such ships -- no one questions the morality of people being born as immigrants or in difficult environments.
I do think generation ships seem unlikely constructs and extremely difficult engineering problems, but I could see where semi-generational ships (ie, for traveling the Hohmann Transfer from Earth to Neptune and back) could be plausible.
KSR's schtick of using the India (or whatever power resides on the Subcontinent) as a hypercompetent 3rd party that supplants the US/China/Russia/etc is becoming increasingly hilarious in retrospect.
I still like his more recent stuff, but it doesn’t have the same shine as his 80s and 90s work. The Mars and Three California trilogies were on another level.
From what I recall the ship was breaking down slowly but inevitably - the ecosystems were slowly collapsing and the human population wasn’t having an awesome time either, and unless the planet had been perfect the situation would have always been dire. Whether ecosystem collapse on a generation ship is inevitable is anyone’s guess (though the biosphere projects don’t fill me with confidence), but to throw people into a 160-year-long journey without knowing whether their ship could actually last that long and without any capacity to make it back seems like a pretty raw deal.
I think people definitely question the morality of having kids in difficult environments. It’d probably be morally wrong to decide to have a kid in the midst of a famine or something like that, where the kid’s predominant experience of life would be some sort of suffering. I’d say that a generation ship gone-or-going wrong is pretty comparable to those circumstances, probably a morally bad place to have a kid.
If we HAVE to try interstellar travel, I think that some sort of relay system or set of stepping stone stations could be good - something where there’s a way back or at least a way to some sort of safety if people decide they don’t want to continue the mission.
> but to throw people into a 160-year-long journey without knowing whether their ship could actually last that long and without any capacity to make it back seems like a pretty raw deal.
So basically every Atlantic or Pacific crossing until the 20th century? Long voyage loss rates were 3-5%. As many as 5% of overland migrants (aka "pioneers") died in transit.
I just can't help but think such thinking reflects a risk-averse mindset biased by relatively recent technology which makes long distance travel very low risk. Long distance travel has *always* been high risk, even on land (war, bandits, weather, poor maps, harsh geography).
Kids turn up frequently in the worst places where you wouldn't think people would be eager to have kids (Gaza, civil-war Syria, famine/war plagued countries). I think for better or for worse, human reproduction is driven by hormone-fueled neurobiology which defies rational thinking, otherwise we might have died out early as a species.
That being said, dumping people into a tin can for 12 light years and just hoping it all works out is dumb, and I'd agree that stepping stones make sense. Though I think there's limited value in building stepping stones past the heliopause. It's not like you could easily "just stop" at a space outpost (killing all your delta-V) 3 light years into your journey to Tau Ceti. Plus if you're into the moral trade-offs of long space voyages, who's gotta go live at the "last stop before Tau Ceti" interstellar space station?
IMHO splitting the ship's assets and people in half (even with their dues ex machina 3D printer) at Tau Ceti was the error. In the Tau Ceti system they had access to a lot of raw materials and probably could have just lived in a greatly expanded space station, possibly long enough to solve the biological problem they ran into on the surface. If they HAD to go back, they should have stuck around long enough to reconstitute the Aurora's original scale before departing.
That book does demonstrate this but in a very silly and hypocritical way where the only characters in the story who actually do the morally awful thing in question are the heroes. Which could have been an interesting twist if the author genuinely cared about the moral implications, especially since the heroine abandons half her population to die on a toxic planet in order to fund the voyage. Instead KSR introduces stasis pods via deus ex machina, letting his heroine skip back to earth to righteously condemn a new generation of prospective space travellers for a crime that they, unlike her, were not going to commit.
Came to the comments specifically to recommend this book. It dramatizes most of the problems you talk about & a number of ones you don't (I shan't spoil them, read the book!). It's quite superb, highly recommended
I heard KSR say (at one of his annual appearances at the Bar Harbor library) that while he was writing Aurora he came to realize how impossible generational space flight would be, but he went ahead and finished the book anyway. It gives us something to talk about.
I wouldn't treat Aurora as gospel. Didn't they literally invent the suspended animation technology that would make interstellar colonization possible at the end?
I may have read other speculative fiction on this subject, so if the following points are not addressed in Aurora, sue me.
What I remember is even if you stipulate suspended animation working perfectly, you still have the problem of small or large degradations of the entire ship to worry about. How many spare parts and repair kits do you plan on bringing? Or do we need to also stipulate nanobots and replicators?
Then there is the micro-organism problem. We evolved for Earth environments alongside of all the other life forms here. Starting over in another environment that is basically similar to ours leads to “is basically similar ever going to be good enough, or will be wearing space suits forever?”
A wonderful book that explores all of this in detail specifically the Moon and MARS, ignoring the interstellar travel issue, it’s called A City on Mars. https://share.google/pexeKygAga1Cp6yLP
The OG of "generation ship" stories is "Orphans of the Sky" by Robert Heinlein. Originally two novellas published in 1941, was later put together into one novel.
And this is the simple answer to the Fermi Paradox. Everything is much harder than we make it out to be. Including not destroying your own planet/civilization on the way once technological progress advances enough to make spaceflight possible.
Interstellar travel is hard, but communication is not. Interstellar communication is something we could easily do now, much cheaper than any given space probe mission. And our next generation of space telescopes will be able to identify planets like earth, so anybody out there should know our planet has life, and could have for a very long time. Yet nobody's pinging us.
It took more than 4 billion years for earth life to develop interstellar communication. It took 300,000 years after our species evolved. There is no guarantee that any of the evolutionary steps, as well as the many contingent technological requirements like fossil fuels, or smelting, would arise (noting that literally not all humans had developed these). It's an assumption on your part, and the part of many, that such communication is easy, which is not born out either by our history, nor the silence of the universe. I believe that assumption is flatly wrong.
Yes, there are lots of steps in the paradox that could be very unlikely. It's just that difficulty of interstellar communication as a technology is not one of them, so the difficulty of interstellar travel is not a bottleneck.
Communication between stars using relatively inexpensive radio dishes, or short pulse lasers with ground based telescopes, is feasible for us now. There's just nobody on the other end to talk to.
Just because it's feasible for us does not mean it's feasible or easy for other creatures. An intelligent species that evolved in the oceans of a water planet would never have any need for such a thing. They might never even conceive of it. The universe could be filled with super-whales, and we'd have no way of knowing, and they'd have no way of letting us know.
As I estimated in anohter reply the recipients of such a message, should they exist are more than ten thousand light years away. So why would you expect a response?
But your estimates are wild guesses at the pessimistic end. The "fermi paradox" is about aliens not being obvious. Well, just assuming colonization is very difficult solves that. Then you just need to explain them not building omnidirectional beacons, or pinging millions of stars one at a time very often. That's not hard to explain: beacons are very expensive, and a serial ping program might take a long time for us to detect, or be something only new young civs engage in.
I...can't help but think we're advertising plenty as it is, and while it's reasonable that most hypothetical Things won't notice...I think there are some invalid assumptions baked into the cake of your premise. To lay flat your assumption set as I see it 1) like us enough to understand the message received 2) advanced enough to receive and parse the message, and 3) not wanting to eat my face out of spite or maybe other reasons. Maybe no. 3 is a bit much--quite a long drive just to eat my face--but the first two seem to me like a math problem with several major unknowns.
We've been broadcasting for maybe 80 years, so given return signal time they'd have to be within 40 light years. That's a few thousand stars, out of around 100 billion in the galaxy. So unless civilizations that could reply it are common as dirt, we wouldn't expect to be detected by now. We might have received a very strong and active broadcast that was just ongoing for millions of years, but haven't yet.
So it seems like we can rule out extremely close civs that are chatty, as well as very high-resource long-duration broadcast programs (ongoing for millions of years to find new civs like us, broadcasting constantly to millions of stars). We would miss civs that listened for leakage radio first but are more distant than very close by, or civs that had broadcast programs that were patient and expected us to do a lot more work or didn't mind it taking millennia for us to happen to hear their ping. Basically we have covered almost none of the search space.
Also please correct my non expert ass but space is much bigger and deeper than any Earth ocean so if I’m 99.99% unlikely to spot say a submarine that’s near the ocean floor, even if i have a super effective scope—how much less of a chance that I’ll pick up an alien signal that i can parse?
Simple calculation. We've found around 5000 exoplanets, none of which are remotely like Earth. Assume that the probability of a sufficiently Earth-like planet that could evolve life is 1 in 10,000.
One Earth multicellular live first arose around 600 million years ago. From that organisms capable of receiving and transmitting extraplanetary EM radiation in the radio region of the spectrum has existed for about 100 years or about 1/6 millionths of time. Combine this with the 1/10000 frequency for Earthlike planets and you get 1 in 60 billion stars have planets. Given the 0.14 stars per cubic parsec density of stars in the Milky War we need a sphere of diameter 11,700 parsecs (38K light years) to contain two civilizations capable of sending and receiving EM messages. The other advanced civilization is tens of thousands of light year away, By the time they detect our signal (should be ever send one) we will no longer be anything like what we were when that signal went out.
Google AI says the Milky Way is at least 100k light years in diameter so your math suggests at least several civilizations here at home. Then there are 2 trillion galaxies!
Other galaxies are hundreds of millions to billions of years away travel time and so irrelevant. Even the few in our galaxy are millions of years away, still irrelevant.
Counter-counterpoint: If wormholes exist and can effectively be used for travel or communication, then you’re back to having to explain Fermi’s Paradox.
There is a quality of subatomic particles called spin that could perhaps solve this problem - change the spin of a lepton and it's pair responds with changed spin instantaneously regardless of distance - but even ignoring the considerable practical difficulties involved in creating a usable communication device based on subatomic particles it still leaves the problem of needing two paired devices - transmitter/receivers, one of which would still need to be sent to the destination.
Long waits between pen pal messages seems like something we can handle. Space probes already have long timelines: the Europa clipper mission began work in 2013, launched in 2024, won't arrive until 2030 and then runs for 4 years. The voyager 1 probe was launched in 1977, and is still in contact and returning results.
That exact thing is a major plot point at the end of the novel “Star’s Reach” by John Michael Greer. It’s revealed that interstellar travel is physically impossible, but interstellar communication is possible and prevalent throughout the universe.
That it takes patience, probably more than we have now. It would likely take centuries just for two civs to find each other by radio survey. But we already do long projects: Voyager 1 is still in contact and has been in flight for 48 years. The ESA jupiter moons mission took 12 years to design and build, and will take 8 years from launch to get there.
The false assumption behind the Fermi Paradox is that any civilization will expand indefinitely to master any conceivable environment, except the only species we know to exist doesn’t do that. Look at that satellite photo of Earth from space. Note that it doesn’t look like Coruscant: most of Earth is uninhabited. Not just the oceans either—huge swaths of land are uninhabited. The western United States between the Great Plains and the West Coast is largely uninhabited. It’s got arable land, fresh water, a reasonably decent climate, and is part of the most prosperous society in human history, yet despite this, relatively few people are willing to try to make a go of it in Wyoming.
Or consider Antarctica: not one single person in all of human history has attempted to raise a family there. There is a whole continent on this planet with breathable air, abundant water (or at least h2o), radiation shielding, normal gravity, normal air pressure, etc where literally zero human beings out of 100,000,000,000 have lived the first five years of their lives.
While it’s true that life writ large has a remarkable tendency to adapt to survive in any environmental niche, individual species rarely stray very far from the environments in which they’ve evolved to survive. The nearest planet with anywhere on it as hospitable to human life as Antarctica has yet to be discovered, but even if it turned out to be reachable in a single human lifetime, we know with a high degree of certainty that no human being will never attempt to colonize it, because no one has ever attempted to colonize the Antarctica-like part of Earth that can be reached within a day or two.
Your comment touches on a very important point, and a problem which the reification of astrophysics has, in my opinion, directly contributed to: a disregard for earth's uniqueness. It's extremely easy to live on earth for an ape with the biological needs of a chimp, but triple the brain capacity. Most of the problems we face are caused by ourselves, not by our environment. Even our most inhospitable environments are absolute paradises compared to everywhere else we've observed so far. I think there may be specific reasons for that related to planetary evolution, but whether it's very common or exceedingly rare, the fact is that it doesn't appear easy to reach such a place.
By implying that space is easy or even possible to colonize, whether terraforming Mars or long-distance travel to more suitable planets, it causes people to disregard how important and special our planet actually is.
So here is my take on the Fermi paradox - let’s say that an alien civilization lasted 10 million years (an incredibly long time by our metrics). Their electro magnetic signal streams past earth for that long - a tiny fraction of earth’s history. The odds of it overlapping with our time as an advanced species capable of identifying and analyzing it would be related to how long we survive in that state. Half a million years looks pretty ambitious at this stage, so the odds of any intelligent life seeing any other intelligent life get pretty slim, even if they do exist for some pretty long timeframes. So maybe that’s the ultimate irony - distance and time make the chances of overlapping pretty poor. Even if we do detect another intelligent civilization, the further away it is the less likely it is to still be present when we detect it, much less by the time anything we try to Send back to them gets there. We would be looking for and trying to talk to ghosts. The obvious solution would seem to be that advanced civilizations don’t last very long even if they do arise with some frequency and that makes them nearly impossible to detect in the tiny sliver of time we have been advanced enough to look for them.
Not really. There is no bar on unmanned spaceships. It takes only one million years for a civilization to spread its unmanned spaceships over the entire galaxy so the unmanned ships should be here.
I think that an easier answer to the Fermi Paradox is that we don't know what to look for. Radio transmissions started a century ago, and we've already found lower energy ways to do those transmissions. It might be that we won't even need to use radar to track air traffic in another hundred years. What will be left for other aliens to watch for? Two hundred years is a drop in the bucket in terms of visibility.
In the other direction, it would be easy to believe that fusion rockets are propelling intelligent life all over the galaxy. We wouldn't see their exhausts unless the rockets were pointed right at us. If they were pointed right at us, what would they look like? Quasars, that's what. (The reality of that theory is that half of them would be blue shifted, but it illustrates that we don't even know what we're looking for.)
Even if you assume an average rate of expansion of 100 years/ly (0.01c, likely achievable with Orion drive), you could still colonize the entire galaxy in 10 million years (blink of an eye in astronomical terms). I don't think the difficulty of interstellar colonization is necessarily a good Fermi paradox solution
My point is, we have no reason to believe that interstellar colonization is a severe Fermi Paradox barrier for an intelligent, technologically advanced species. Based on what we know about physics, it should be possible to colonize a galaxy in a relatively short period of time, astronomically speaking.
The universe has likely been able to support intelligent life for at least a billion years before it emerged on Earth. If an alien civilization in our galaxy had developed spaceflight 10-100 million years ago, it should have expanded to detectable levels by now based on what we believe to be feasible under even our current, limited understanding of physics.
There may be other reasons that interstellar colonization is infeasible, but I dont think it's an assumption we should default to just because it would be infeasible to us right now, when we've barely even explored our own solar system.
You need to disabuse yourself of the idea of an “M-class planet”. That is the second biggest fantasy Star Trek indulges in to sustain its premise. Everything we know about biological evolution and astronomy suggests that interstellar colonization is impossible. Organisms tend not to survive outside of the environments in which they’ve adapted. So for interstellar colonization to be possible, a species would need a second planet nearby with conditions similar enough to its home planet that establishing colonies there would be a worthwhile endeavor. Finding even one such planet nearby is wildly improbable, let alone a whole network of them, each close enough to the next that the species could expand indefinitely.
I understand that there are no “M-class” planets. Any habitable planets in the galaxy other than Earth will only exist due to terraforming. However, I don’t think planets will be all that important to human civilization in the distant future. Eventually, I would expect most people to live in O’Neil cylinders for the simple reason that a Dyson swarm of such habitats could support a population may orders of magnitude higher than Earth alone. In any case, I agree that we’re not going to find any habitable planets through interstellar colonization.
Why would anyone terraform a planet? Why would anyone build a Dyson sphere/swarm? They’re both fantastically expensive undertakings. A civilization capable of doing either is capable of improving Earth to the point that they’re unnecessary. Consider that it’s within the realm of technological possibility right now to build a permanent habitat on the moon. But how many people would want to raise children in the kinds of permanent moon habitats we could build now?
The reason space or extraterrestrial colonization will never happen is that there will always be a huge gap between the lifestyle a society can provide on Earth and the lifestyle it can provide to dwellers of the colony, and no one will choose the colony over Earth, especially not for their children.
Carrying capacity. You can only improve the Earth so much before you reach a hard limit on the population it can support. While we're currently seeing declining birth rates, that won't continue indefinitely. There will always be groups in society that reproduce at high rates, like Mormons and Amish, and these will tend to increase as a proportion of the population over time, increasing overall birth rates. In the long run, we should expect the population to increase to whatever level can be supported. When that happens, we may resort to population control, but not everyone will want to limit their family sizes. At that point, only place to go is up and out. Of course, by the time we reach planetary carrying capacity, it would likely be trivial to build rather comfortable space habitats due to technology and orbital infrastructure. As for the expense of building space habitats, they get cheaper in relative terms as a) the amount of orbital infrastructure increases and b) the amount of energy available to civilization increases.
If we have enough surplus to build habitats in space that can house nontrivial numbers of people, then by definition there’s no problem with our carrying capacity. Carrying capacity is a function of the amount of available resources
Not impossible, necessarily, but I do think it's far harder than sci-fi makes it out to be. And I think that's because a lot of sci-fi is written by people with some understanding of astrophysics, and maybe adjacent fields, and comparatively little about sociology, biology and geology, the stuff of life and natural resources.
But more importantly, I think it's unlikely a rational, self-interested society would ever create such a thing. It's a massive investment, and to what end? Why would I ever work on such a project? Is that feeding my family? Is that saving my planet?
And I have no problem with such Von Neumann machines as a sci-fi trope. It helps us think about the problem, which is a great thing. The problem I have is when ignorant people take fiction as proof that something is possible or even likely. I assert that it may not be possible, but is definitely exceedingly unlikely. And the evidence is both our society, and also the absence of others.
We are (among whichever others exist) universal nerve endings. What we imagine is possible, unless, that is, system’s theory arrives to cull the outreach. That said, I do believe barriers are there to be broken (just not in the Trump/Musk/authoritarian/ technofeudalism sense – among others)
We would not recognize extraterrestrial life anyway, much less intelligent extraterrestrial life. Our concepts of life and intelligence are determined by our earthly existence. We might not even be able to sense them at all if we encountered some.
The bloody obvious solution to the Fermi paradox is that there are no other civilizations in the universe. Why do people always assume the case unsupported by any evidence whatsoever then try to rationalize it?
So why are there no other civilizations? The answer to the paradox is not as easy as you make out. Where along the line of development did other potential civilizations stop? We don't have "proof" that life is likely or unlikely. We don't know how many planets in the galaxy are capable of evolving life, or to what degree. Nor do we understand what encourages or discourages it from attaining sufficient complexity to exhibit eusociality, language, self-awareness, tool use, science, etc.
The answer to these questions, which makes them relevant to this discussion, probably *requires* interstellar travel, or comparable power and technological complexity—say, for building very large and detailed simulations.
Nobody's saying (well, probably some are) that there are no other civilizations. They're saying there are no other civilizations that can travel to visit for Thanksgiving dinner, or Earth Day, or....at all. The laws of physics are what are keeping us all in our lanes, so to speak, and the sooner we accept that the better (know how many people could have homes, and nutrition, and educations, and families, and futures, on the money Musk is wasting on launching to Mars--or, rather, preparing the infrastructure to launch a necessarily-doomed expedition to Mars to 'pursue man's destiny?'). Why do we always have to learn the hard way?
Hm. How many invalid assumptions--as there would no doubt be several--would it take to make this "large and detailed simulation" a fever dream that either leads us nowhere, or leads us astray? Asking for a descendant. To be more fair--what assumption sets must we necessarily accept or reject when attempting to create these simulations, if that's the way? (You can not believe me when I say so, but I think myself to be agnostic and want to explore the idea.)
Expanding on your second point reveals the answer to the Fermi Paradox. We can make some inferences about how likely it is that life evolved elsewhere from how quickly it evolved here. Assume that on any Earth-like planet, life will inevitably evolve there on approximately the same schedule as it did on Earth. (This is a wildly optimistic assumption) That suggests that the fraction of Earth-like planets with intelligent life is equal to the percentage of Earth’s total lifetime it was host to an intelligent species. So we should expect 0.0004% of Earth-like planets to host intelligent life. Now, intelligent life has existed on Earth for 200,000 years, but it’s only in the last 100 or so that we’ve been sending detectable signals. So we can estimate that only .05% of intelligent life that exists is even detectable. Overall that gives us 1 theoretically detectable civilization for every 45 million Earth-like planets.
Now assume every star is home to an Earth-like planet (another wildly optimistic assumption). The average density of stars in our immediate neighborhood is 1 per 16 cubic light years. 16 * 45 million is 720 million. The cube root of 720 million is about 900. In other words, in the face of two wildly optimistic assumptions, we should still expect that the nearest detectable intelligent civilization is at least 900 light years away.
The fundamental assumption of the Fermi Paradox is that there’s nothing special about Earth. But following that logic to its conclusion suggests that we shouldn’t see any signs of other intelligent life, not that signs of it should be everywhere. In order for there to be abundant intelligent life in the galaxy, there must be some way in which Earth is unusual. We can our own planet’s history as baseline assumptions for values of the Drake equation and toggle which ones we need to to figure out which parameters need to be different and by how much to have a reasonable expectation of other civilizations.
Dude, there are many more oddities than that. There's good evidence that you don't get our biospherical complexity unless you have a strong magnetic field. How many planets do you think get hit by another planet early in their development, creating our dense, radioactive core? Based on the heavy metal mix, our system was created from dust that had been through at least two previous cycles of supernovas, and that limits how early in the universe's history a life-bearing planet could come into existence.
The super-easy answer to the Fermi Paradox is that we are totally guessing at the components of the Drake equation.
No argument. I have no doubt there are thousands, millions of civilizations of every shape size and intelligence out there. Much of this discussion, though, is about us all getting together for picnics and music festivals and concerts with blue-tubed divas. That ain't happening
We expect this because the formative years of science fiction happened when they did.
In the 1950s, jets were new, and rockets were about to go into space.
In the early 1900s, powered flight was new.
In the 1850s, steam trains and boats were massively increasing transport options.
In the 1800s, practical steam engines were new.
In the 1750s you had horses and sails, just like the Babylonians.
Someone writing SF in its early years extrapolating forward would reasonably expect transport tech to keep going on this trajectory.
Similarly, in the early years of SF colonial and explorer-based fiction were still popular and unexamined, but the frontiers where it applied were closing or closed. So move the setting to space.
So we get super-fast space vehicles exploring and colonizing outer space.
Let's talk about the physics, because there are some very common mistakes people make.
Let's suppose we could propel a space ship at .9999c. It's obviously a futuristic goal, but it's not Harry Potter. We already propel things orders of magnitude faster than that at CERN. Let's suppose we're not bothering with the closest stars. Let's say we're going to Vega, which is about 30ly away. People who haven't studied relativity sometimes mistakenly think that the trip has to take at least 30 years, but in the "proper time" for the people making the trip it would actually take only 49 days. (For anything traveling the full speed of light, the "proper time" travel time for any distance is zero.) 49 days is significantly faster than the first human trip to Mars will take. However, for the observers home on Earth it will appear to take 30 years for the trip and another 30 years to get the signal back showing the landing. That shows that yes, if interstellar travel happens, it will likely be for colonization, not exploration.
A grain of sand traveling at .9999c would indeed have the kinetic energy of a small nuclear explosion (a grain of sand at .1c would only have about the energy of a 1 ton vehicle travelling 100 MPH), but particles that large in interstellar space would be extraordinarily unlikely to be run into. Micron dust yes, but that's more manageable.
The biggest challenges are propulsion, fuel, and shielding. For propulsion let's say we could achieve and sustain indefinitely 1g of acceleration. It's obviously a futuristic goal, but it's not Harry Potter. We very reliably achieve more thrust in spacecraft and haven't been doing it for that long. The problem is the fuel and the efficiency, not the physics. If we could sustain accelerating 1g acceleration half way to Vega, then turn around and decelerate at 1g the second half of the way, we'd have peak v of around .9999c, and the total trip would take 6.6 years. (Link to math below.) Still very reasonable for colonizing Vega.
For efficiency we'll want to assume we have antimatter fuel and a propulsion system that can use it, because that's the only way to have a storage mass to energy ratio which makes it plausible. Obviously a futuristic technology, but not one that defies physics.
As to the question of why we'd go, it depends on the time frame. The sun will not last forever. Once it starts transitioning to a Red Giant, survival on Earth will eventually become impossible as a matter of physics, not as a matter of technology.
But it gets even more interesting to apply the same reasoning for much larger distances. The Andromeda galaxy is 2,000,000 light years away. Using the method of 1g half way there then decelerating 1g the other half way, we'd peak at around 0.9999999999c, and it would take us 28 years to get there. On our trip to Vega, the cosmic background radiation became "blue-shifted" into a red hot disk in front of us, but at the speed we'd reach going to Andromeda, it would become much much much hotter. The view of the cosmic background radiation and of andromeda in front of us would be compressed into a microscopic spot. The light from andromeda would become X-rays/Gamma rays with the energy flux comparable to sunlight, and the cosmic background radiation's would be UV or X-ray with an energy flux with a couple hundred times the energy flux of sunlight. This creates two interesting questions. First how do you shield it so the spacecraft isn't instantly vaporized, but second, what if you could capture that energy and use it for propulsion so that that problem actually solves the problem of the absurd amount of antimatter fuel you would need for such a trip, because once you get to a certain critical speed, you can use the blue-shifted cosmic background radiation as your energy source instead of stored fuel. Is this a physics problem or a technology problem? Less clear, but it's at least plausible that making the 28 year trip to the Andromeda galaxy is just a technology problem. Of course if you're going to signal back home that you've arrived, it will take 4 million years for the message to get back, so everything about this trip is definitely one-way.
Most of the math in this is at this link, which is one of the best static pages that's been on the Internet in one form or another for almost 30 years:
This is also why, after a certain scale, interstellar travel can only ever make sense for conscious beings and never for probes. No Earthling will ever send a probe to Andromeda, because physics flatly prohibits ever getting a message back to Earth in less than 4 million years. But physics doesn't prohibit a traveler going at relativistic speeds getting there in their lifetime.
Relativistic speeds are practically impossible. At such speeds every hydrogen atom the ship encounters will collide with the impact of a cosmic ray. The required shielding would be immense and would further increase the fuel requirements. The shielding-fuel conflict means we practically cannot get much faster than a third of the speed of light.
Cosmic rays aren't so bad. A hydrogen atom travelling at .9999c has a tiny amount of energy. A ten millionth of a Joule. I don't think there are enough of them in interstellar space to be an issue.
Coincidentally or serendipitously, I'm writing a novel about a colonist mission to the planet of another star. Your comments have been of great help. Why it's taking me so long: there is so much science to be studied. Compared to cytology, rocket science is like Lego! Also as I age, my math skills are steadily departing. Wrongly or rightly, ignoring relativity, I calculate acceleration times as follows:
Speed of light: 300,000 kilometres per second, or 300,000,000 metres per second.
Acceleration of 1g: 9.81 metres per second squared.
Time to speed of light: 300,000,000/9.81/60/60/24: 354 days
If Vega is 28 light years distant, the ship would accelerate and decelerate for 1 year each, and coast for 26.
(My ship the Cygnus travels at Vmax 0.4c as that is the most that the space debris pulverizing systems can handle.)
Google AI overview tells me that upon annihilating with matter, one kilogram of antimatter releases 1.8 x 10^17 joules of energy. That's quite a lot. Naturally, the ship would also have to carry the matter to be annihilated with. I'm not very happy with my reasoning here; please will you help me out?
Mass of spaceship: 1000 tonnes or 1,000,000 kilograms
(Yes it can be done, even with present-day carbon fiber, never mind what new materials will be available in the future.)
Joules to accelerate 1kg by 1m/s² : 1
Joules to accelerate 1.000,000 kilograms by 1m/s² : 1,000,000
Joules to accelerate 1,000,000 kilograms by 300,000,000 m/s² : 3E+14
Which is well under the Google number. But it's such a small quantity that I'm just a wee bit skeptical. Help!
Unfortunately, with relativity the math is a little more complicated than that. Fortunately, AI is very good at it. If you ask either Google AI or ChatGPT 5 "Using relativity, and 1g acceleration, what's the time and energy consumption required to accelerate 1000 tons to .4c?" It looks like they both use the right formulas, and the right steps, and get to the same answer, though ChatGPT 5 provides a lot more detail, namely to reach that speed:
Thanks, I can't remember where I got it but I used the 1/(sqrt(1-(v²/c²))) formula to calculate the energy curve. Days are close, joules wayyy out but the fuel load is still manageable.
Once you're cruising at .4c, though, if you've stopped accelerating, the rest of the math is easy. Your Lorentz factor at that speed is .9165, so your distance to your destination is 8.35% shorter than it would be if you were at rest because of relativistic length contraction. So the time to get to your destination while cruising at .4c is just the distance from the ship to the destination reduced by that 8.35% divided by .4c. Relativity helps you get there faster.
There a non-conscious beings that aren't simple "probes" that it may be of interest to send. For example, ships designed to replicate themselves, find other alien species, and uplift/guide them.
We would not, under any circumstances, want to uplift/guide any intelligent lifeforms. All that does is create competition for what would be, under geologic timescales, finite resources. It's retarded to even contemplate. What we would want to do is either A) Wipe them out or B) Leave them better. Option B is the kind, merciful option but under the caveat that we wouldn't be expecting them to get into space on their own. Otherwise Option A is the realistic option
That is just re-stating the problem with a different description of Harry Potter’s wand. How to accelerate a large ship to .9999c - and decelerate to land? An ocean liner carries people for a week, no cargo for colonization or spare parts for a long voyage, tiny engines, and small fuel tanks. A colonizing starship would be far larger. Its fuel and boost mass requirements would be larger than gigantic.
Fast boosts over interstellar distances are beyond any technology we can imagine (ie, they’re magic). Many people have explained this. Perhaps most clearly is Jerry Pournell in “Those Pesky Belters and Their Torchships” - Galaxy, May 1974. In brief, it requires mind-blowing massive long-duration power source and even larger stores of boost mass.
It has been frequently reprinted. Here is the text:
And the fact that Pournelle is pointing out correctly that it's all about the energy requirements brings to mind Nikolai Kardashev, and the Kardashev Scale which describes a "Type 1" civilization as one that can store and consume all of its planet's energy, and a "Type 2" civilization as one that can store and consume all of its star's energy. Type 2 technology is close to unimaginable, but if a Type 2 civilization ever existed, then it follows that interstellar travel would be trivial for it, since it's the storing and using of energy on that scale that is the main issue.
Pournelle is pointing out the implausibility of mining asteroids with *near-future* technology. The trip to Vega would be impossible with near-future technology, no question. But it could be done with plausible-according-to-physics technology. What Pournelle is pointing out is the energy constraints, which is definitely the biggest barrier. What we'd have to do is crazy by modern technology, but unlike Harry Potter, we can write all the physics equations for how we'd do it. The technological steps we'd need are:
1) Convert a massive amount of energy from the sun into matter/antimatter fuel. There's no existing tech for it, so it's far-future, but there's no reason in physics why we couldn't do it.
2) Invent a way to store large amounts of antimatter. Again, far future tech, but we already do it at small scales at CERN.
3) Store one ton of that fuel (886 kg, calculation from the link in my post) in a spacecraft for the Vega trip.
4) Develop a propulsion engine that can convert matter/anti-matter fuel into 1g of propulsion. No existing tech like that for sure, but you can easily write the physics equations for how it could conceivably work.
1/ First, he is not focusing on asteroid mining - but on propulsion systems.
2/ You mention only one of the two constraints Pournelle discusses. The second is boost mass. To accelerate to relativistic speeds and then deaccelerate would require a bizarre load of both fuel and boost mass. A crude analogy would be a coal burning (steam engine) cargo ship capable of circumnavigating the world.
3/ Stating the energy required for a trip to Vega is not useful, without mention the weight of the ship (excluding mass for fuel and boost) and duration of the trip (by the ship’s clocks).
Yes, sorry I misread what the chart was showing. It's 1 ton of fuel per kg of payload for a Vega trip. So it would be many tons. Again, wild to imagine, but not magic in the sense of being contrary to physics.
That seems reasonable. For what duration trip to Vega? That makes a difference when calculating payload. Supplies for a day or a year or 10? Also, what boost mass is needed (that is, what efficiency of the drive)?
Also, what is its radiation shielding? Massive ice or metal in front?
If the ship, loaded, is like the Nimitz (~100k tons + 100 tons antimatter + boost mass + fuel & boost mass for the boost mass) - that would be quite a starship.
As you said, it would not violate our laws of physics. The author’s comparison to magic was, I believe, a literary exaggeration. Such a ship is so far from our tech as to require multiple tech revolutions. I doubt we can even imagine the nature of a society so far in the future, with such advanced tech. Hogsworth’s magic world is as good a model as the usual sci fi world.
1/ First, he is not focusing on asteroid mining - but on propulsion systems.
2/ You mention only one of the two constraints Pournelle discusses. The second is boost mass. To accelerate to relativistic speeds and then deaccelerate would require a bizarre load of both fuel and boost mass. A crude analogy would be a coal burning (steam engine) cargo ship capable of circumnavigating the world: 99.999% of its weight would be coal.
3/ Stating the energy required for a trip to Vega is not useful without mention the size of the ship (excluding weight of fuel and boost mass) and duration of the trip (by the ship’s clocks).
"The Forever War" deals with dilation as it affects military conflict. It begins in 1997; by the time the narrator returns from a series of ever-deeper sorties it's thousands of years in the future. Human society is unrecognizable, and the conflict has long been settled — not by battle but by the parties being able to communicate the misunderstanding that led to carnage. Staging points from which the human forces departed have staff only from a sense of obligation to those who had launched from them.
"What are we fighting for? Don't ask me, I don't give a damn!"
Time dilation occurs only when an object is accelerating. If one reached cruising velocity (presumably near the speed of light) no time dilation would occur.
The main advantage for the traveler is actually the length contraction, rather than the time dilation. The distance to the target shrinks with the Lorenz factor.
Right. I was just addressing the misconception (that I had for many years) that time dilation is relative to velocity, but Relativity ties it to acceleration.
Your original conception was correct. Time dilation has nothing to do with acceleration. It is strictly a function of relative velocities (and gravity wells)
Cannot remember the reference, but I believe I read something a long time ago about mass approaching infinity as it approached the speed of light. Hopefully we loose all that weight as we slow down or our destination will overwhelmed with some very chubby people.
Honestly, it’s probably better to set the bar lower and use more primitive but currently feasible fission/fusion based propulsion maxing out at 0.1c and go all in on expanding to every rock in the solar system due to the dramatically shortened travel times. Although if we’re still exploring realm of basically science fiction tech, rather than antimatter, we could spend maybe a century or two just building enough orbital solar farms close to the sun to condense massive amounts of energy into a tiny point to create a minuscule black hole, which could power spacecraft with enormous amounts of energy indefinitely as long as you periodically chucked any sort of normal matter into it to stave off collapse due to evaporation. It’s still phenomenally dangerous, but probably a lot safer than storing antimatter for prolonged periods of time, plus you don’t have to expend tons of energy making new antimatter to refuel, just throw some normal space rocks or collected hydrogen gas into it and allow the black hole to do the mass/energy conversion for you via hawking radiation.
It's important to keep in mind though that you don't actually have to send signals back by signal. If you're making a 28 year trip to Andromeda, you can theoretically make a 28 year trip back with letter or 10,000, thus allowing very slow but real communication between the two locations.
You can make a the 28 year trip to Andromeda and the 28 year trip back, but when you get back, the Earth and everyone on it will be 4 million years older.
Antimatter drive: converts one hundred per cent of its fuel to energy (Penrose). If the drive is shooting particles out of its butt at very close to the speed of light, a microgram might create thrust of a thousand tons. Verdict: possible. But I'm just your everyday Dumas and might be shooting out of my butt...
Space debris: huge problem. One solution might be a very long cylinder of aerogel, a couple of kilometres thick, in front of the spacecraft. Another might be a Star Wars Death Ray blasting incoming matter into plasma. Verdict: possible.
Shielding: huge problem. Sand is only a partial solution for two reasons. One, the mass. Two, incoming matter won't create the normal Hollywood explosion because there's no air, but the sand will explode. The Van Allen Belt is a kind of Faraday Cage. If that can be scaled down to a reasonable size, my verdict is: possible.
Artificial gravity: ridiculously easy. Acceleration and deceleration create gravity, but let's say that the supply of antimatter fuel is finite and for much of the voyage, the spaceship will be coasting and gravity will come from centrifugal force. The inhabitable parts of the wheel-type spaceship won't be a continuous ring. They will be modules like large shipping containers, ten or fifteen metres in cross-section and maybe forty metres long. The wheel has spokes. At the end of each spoke is a fitting like a turnbuckle. A module fits inside the eye of the turnbuckle, and can rotate within that eye. In the changeover from acceleration to free flight, the turnbuckle turns ninety degrees and the module turns ninety degrees within the eye. Result: flat floor, direction of down within the module is consistent.
Dzhanibekov: the spaceship will need some sort of ballasting system, like water being pumped around, to prevent any chosen diameter from becoming a privileged axis. Otherwise, I don't think there's a problem. The number of points on the circumference of a disk is infinity to the power of infinity and there's no reason why any random point and its diametrical opposite should lie on a privileged axis.
Chow: hydroponic farms.
Genetics: a mission of say one hundred colonists may not have sufficient genetic diversity. At present there's a ban on gene correction. That would have to be lifted.
Interstellar travel requires two magic technologies, namely antimatter drives and radiation shielding. Before these become reality we're probably looking at a minimum of fifty years from now.
50 years? First to capture enough energy to create large quantities of antimatter (which I think would have to be space-based), then to create the antimatter, then to store the antimatter, then to create practical propulsion using antimatter, I think 500 years is probably unrealistic. I think closer to 1,000.
For the genetics, if you send 100 colonists, even if you genetically remove any disease, after enough generations you basically have a population of clones, which isn't good. I think for colonization you'd want to take frozen embryos or frozen gametes with you so you bring along the genetic diversity you need for when as the population start growing. I guess if things are sufficiently advanced, another option would be to use genetic engineering once there to introduce artificial genetic diversity to each new generation.
You veered into fantasy with “assume antimatter fuel”. Naturally occurring antimatter has long since annihilated itself, and the laws of thermodynamics preclude artificially created antimatter as a fuel source.
Yes, creating antimatter fuel will not be 100% efficient, so the process will require more energy input than the ultimate output. That doesn't mean that thermodynamics prevents us from creating it or using it. For the amount of energy needed, we would presumably use the Sun as an energy source.
Yes, but you’re not using the antimatter as an energy source the way coal, oil, uranium, or renewables are used (actual net positive energy to fuel civilization) but rather as a dense form of energy storage for propulsion (like using any of the aforementioned energy sources to charge up an electric car battery or make hydrogen for fuel cells).
At speeds like that the CMB is blue-shifted to such high-energy radiation coming at you head on, there's nothing that can continually propel you at those speeds.
Even if you had perfect mass-to-energy conversion, or a power source behind you, there is just no way it's possible for traveling somewhere humans haven't been before. ~99% the speed of light is about when these problems really start to become prohibitive.
I mentioned that in my post. According to my calculation, at .9999c, which is peak velocity for a 49-day Vega trip (30 lightyears), the CMB becomes a red-hot disk in front of you, but still much lower power than sunlight from Earth, so that doesn't become a problem.
It's definitely a problem at 0.9999999999c, which would be the peak speed for a 28-year trip to Andromeda, which at that point the CMB becomes a stream of x-rays with hundreds of times the power of sunlight from earth. But the interesting possible solution would be trying to use it as a power source.
That's exactly the reason for antimatter, because matter-antimatter annihilations are the only way to turn matter completely into energy. So anything else would require orders of magnitude more fuel mass.
Generating one, yeah probably, although storing and keeping it fueled up might be a decent amount easier, given that as long as you can just chuck some normal matter like some space dust, or a rock, or even non-vital chunks of the ship into it to keep it pumping out power and avoid it totally evaporating and exploding, while antimatter would need constant magnetic confinement in a total vacuum free of any trace of regular matter to avoid catastrophic detonation.
“Interstellar Space Travel Will Never, Ever Happen the Way You Think It Will.”
My vision of interstellar travel is a gradual expansion of civilization. It is far easier to create living space in O’Neill cylinders than to terraform planets, so I imagine a future where the majority of humans live in cylinders orbiting various bodies rather than on planetary surfaces. As clusters of O’Neill cylinders extend outward to the Kuiper Belt and Oort Cloud, they will approach the equivalents of other star systems. Colonization will then happen in reverse—starting in the outer orbits and moving inward.
For people who have never known anything but an O’Neill cylinder, spending 10–20 years aboard one to travel between destinations wouldn’t seem unreasonable. Once colonies bridge the gap from one star system to the next, interstellar “freeways” could be established. Lasers or other energy sources would beam power to spacecraft, making it possible to reach nearby systems (such as Alpha Centauri) in 14 or 15 years. Not comfortable, but doable—without requiring a generational ship.
Another likely scenario is that space travel will be undertaken primarily by artificially intelligent robots. They could slow their clock time or enter hibernation far more easily than biological humans. In that case, non-human entities may be the ones to experience the interstellar adventures we imagine. If they haven’t eliminated human society, perhaps they’ll beam back stories of their journeys and tell us what it’s like and our posterity will get to experience it vicariously through our robot descendants.
I suspect the machine solution is the most feasible. It requires more sophistication, and more miniaturization, and mass production, and massive redundancy. If you fire a trillion tiny bullets full of highly compressed computation and mechanization—basically artificial DNA—then enough hit your target to start a highly accelerated and pre-programmed artificial evolutionary system. Ten years later, you have a fully functional advanced machine colony. This is simply a variation of Von Neumann's idea.
One other comment. While worrying about not being able to visit the stars, let’s not lose sight of how amazing it would be to visit the other planets in the solar system. One of my favorite YouTube videos of all time: https://youtu.be/iiPmgW21rwY?si=-0Bfuv9IVKXcPsCg
No human being can develop normally, physically or mentally or emotionally in one of those cylinders. As far as doing it with robots? That's little more than an unmanned probe. Why do it? So that some kid eating his corn flakes can marvel at the reports coming back?
Nobody outside a few SF geeks would ever care. Much cheaper for us all if you Sci Fi types would just read a Ray Bradbury book.
Why wouldn't a person be able to develop normally in an O'Neil cyllender? Each one would have rotational gravity on par with Earth and would likely have a habitable area around the same size as NYC (based on O'Neil's original specifications)
Good article, Jason. Another spin on what you're saying is that there's no reason for anyone to do this. No organization can profit off the expense of such a trip, there's not trade that can make up for it, no nation will get glory from it in the time frame any ruler cares about. No pilgrim will find a better life on an alien world when they won't live to set foot themselves on it. The personal impulse to explore the unknown falters when the explorer will never see anything but the confines of their ship.
The thing people should be connecting here is that the reasons to never explore the stars, even via multi-decade probes, are the same as the reasons we're wrecking the earth and treating geopolitics like it's the last turn in a strategy game before the board gets put away.
If we were the kind of society that truly cared about the future of humanity a hundred years from now, we would also be the kind of society that found it much easier to imagine the point of interstellar projects.
It's hard to make people care about a time and place they'll never see. We might have been able to before, but... well, look at the reaction when a billionaire shoots a rocket towards Mars, it's all about how that proves we need to tax them more, etc.
In the case of this billionaire, it's one of a thousand pieces of proof that we do need to. Especially when his reasons for wanting to explore Mars range from the impossibly stupid (colonization) to the entirely self-interested (billionaires running away from the earth they destroyed, so, also colonization).
The Earth is far from destroyed, and neither Musk nor Bezos invented fossil fuels.
But even if they did, them advancing space travel out of their own pocket is a virtue in my estimation, even if it will never live up to the promises of Star Trek.
In any case, my point in mentioning it wasn't that tax rates are perfect, but that we aren't a people who will wish to explore space any longer. I think this is some evidence in favor.
Most of the technical and cost issues go away with time as Human civilization because so rich that interstellar travel becomes something that can be done as a lark.
The issue remains the basic physics. It will take multiple lifetimes to go to other star system. This means the concept of *traveling* to the other star becomes meaningless, as I explain here:
Physics does not require multiple lifetimes to go to another star system, or even another galaxy. With constant 1g acceleration, you could go to the nearest star (4.3 ly) in 3.6 years, to Vega (27 ly) in 6.6 years, or to the Andromeda galaxy (2,000,000 ly) in 28 years.
In relativity, physics places no limit on the proper time duration of a trip, only on the observed time from a fixed frame of reference.
Constant one-g boosts are the equivalent of Harry Potter’s magic wand. Many have explained this. Perhaps most clearly by Jerry Pournell in “Those Pesky Belters and Their Torchships” - Galaxy, May 1974. In brief, it requires mind-blowing massive long-duration power source and even larger stores of boost mass.
It has been frequently reprinted. Here is the text:
The author did mention that the problem with high speed travel was the risk of collisions destroying your space craft. Are we confident that some form of feasible shielding would prevent this?
That’s a problem. But not just collisions. At high speeds atomic particles and radiation become serious threats. Commonly proposed solutions are a large body of ice or metal in front of the ship. Of course, this extra mass makes acceleration and de-acceleration become more difficult.
I don't think risk of collision would be a serious issue, compared to the others. The only likely collisions in interstellar space would be micron-scale dust and individual atoms, not grains of sand. A grain of sand at .9999c would indeed carry the energy of a small atomic bomb, but would be unlikely to encounter. The likely power absorption from the micron-scale dust in interstellar space would, napkin calculation, I think be around 30 kW per square meter. A reentering Earth orbital spacecraft has to shield for an order of magnitude more than that.
Radiation, deceleration, collisions and genetic diversity seem to me to be the biggest, most obvious impediments after, of course, TIME. we are not going anywhere and that may be the ultimate irony of life in the universe. Just seeing another planet w life, much less intelligent life is absurdly remote. Our own electromagnetic signatures are barely 100 years old - anything remotely sophisticated more like 75. So we have sent a weak, diffused signal as far as the nearest few stars. Let’s say they were detectable at distances that include significant numbers of stars - maybe 1000 light years. Odds are lousy for there to be any intelligent life in that range, but even if, that’s 900 years from now. And intelligent life? If not for a 1-in-a-bazillion asteroid hit at the right time and place, earth is still dominated by reptiles that don’t need fire or metal to continue dominating the planet. We should be researching how to survive another asteroid hit - subterranean, sub-sea, sub glacial societies. Populated by Volunteers who can stay for discreet times. It’s the reality we know.
Well sure, can't speak to what we might do when we get infinite rich.
But absent some magical Unobtanium, trade won't finance interstellar colonization, because there's nothing we could find that would make up for the expense of the round trip. Anything we need from another star we'll have learned to make or do without long before we bring it back!
Energy returned on energy invested. No such space travel will occur because the payoff is impossible to define, whereas the cost is, to paraphrase the author, unlimited.
Space travel is a sham.
Anecdote: my father was an aerospace engineer, a propulsion guy. Worked on the Mercury and Saturn projects, met Werner von Braun (probably in Huntsville. He went there often). Jet Propulsion Lab as well. But after the moon landings, all that got shelved. His final projects were all D&D business (death and destruction) for the military. That included the Tomahawk cruise missile. The space travel stuff was not remotely cost effective and when I asked him why we did it, he drew a blank. He knew it and never bemoaned having to move on. He was an engineer and they are practical guys.
Lastly, the seemingly unlimited $ coming out of Washington gives too many people the idea that anything is possible, including space travel. It's called hubris. Once reality hits and the phony money stops, all pretense about our expectations will stop as well. That will include space travel. Won't keep satellites from going up. But we aren't going to Mars.
One of the things people forget now is that during the Apollo program, public opinion was mostly against it. I've read that the timeframe of the Apollo 11 mission itself (a couple of weeks, basically) was the only point where Apollo's favorability rating hit 50%.
A lot of people (enough for politicians to take notice) thought it was neat, but also a huge waste of money that could better be spent elsewhere.
I might add that the intervening half-century, unmanned NASA ships have done all kinds of fantastic things, but manned NASA spaceflight post-Apollo 17 has been indescribably lame: We've spent the last 50+ years repeatedly testing whether humans can survive extended periods in a pressurized container in low Earth orbit. The answer is Yes, but we keep running that same experiment over and over. The scientific community long ago lost interest in manned spaceflight and our orbiting space stations because every conceivable experiment that can realistically be done in low Earth orbit has been done so many times that we already know what the results will be before the craft even launches.
The cost of putting a pound into orbit has dropped dramatically in the last few years because of one thing: reuse. SpaceX expects to get many, many uses of each first stage. The Dragon capsule going to and from the ISS is mostly reusable. There are approaches that could drop the cost even more.
Won't matter. Once the funny money stops, the fight will be on for the remaining loot. Trump and his gang are front-running the inevitable by investing in projects before announcements are made. But at least these are infrastructure investments that will eventually benefit the country.
Unless it is a military related project (and many space projects are either openly or thinly veiled military driven) any space project will have to get in line with all the other lobbying efforts. Good luck with that.
Maybe im missing something here, but we dont have a lot of options do we? The sun will balloon into a red giant and nuke the earth. If we move to pluto or something then we dont have access to solar energy anymore. That means we need to jump ship for another star… or just die.
In several billion years the sun will balloon and swallow the inner solar system, yes. Several billion years. Life on earth, and this is including the period of several billion years where it was just a soup of unicellular life, has existed for less time than the time it will take from now until that happens. It's just not at all a relevant problem.
Im replying to a comment saying “there is no reason to do this”
The essay is titled “…will never ever happen”
But it must and probably will… or we will die. Its probably easy to explain the necessity of a generation ship when you can show your kids a video of your planet fucking exploding.
The human race will be long, long extinct by the time that the Sun even begins to lose fusion pressure. This isn't even doomerism, this is 5 billion years! That is an unfathomable amount of time! Humanity could evolve into something different, could upload themselves into a higher dimension, could prove that everything is a simulation after all, get sterilised by gamma ray, we could wipe ourselves out through some means or another, any number of ways.
There are reasons to want to expand beyond Earth, I personally am of the opinion that if you can explore somewhere, you should, but this just is not in the realm of actually being a relevant one.
Why can't trade work? We have mechanisms for enforcing actions over a long time-span, and in hundreds or thousands of years, life extension technology could plausibly assist here too. Communication and enforcement is harder, but we adjust the terms of the deal to suit. I agree there are barriers but they don't seem insurmountable.
It's not impossible, but the benefit have to outweigh the cost for it to be a motivating factor. And the cost is (I can't help it) astronomical. So you won't be hauling produce, obviously, but any other manufactured goods are senseless to haul.
There are a lot of things that were once assumed to be impossible that have since become possible. But there are a heck of a lot more things that were once assumed to be impossible that haven't become possible.
I figure the difficulty of achieving interstellar travel of any sort, short of a suicide mission, might exceed even the difficulty of turning this ship we're all on around in time for anyone alive today to ever enjoy justified hope for the future.
Yes, and the New York Times published articles by scientists in the early 20th century saying that rocket flight was impossible - just a decade before it succeeded.
But you are underestimating the orders of magnitude involved, which was the whole point of the article. You might want to give it a careful read and showing where it's wrong, not just a flip dismissal.
Just because Past Kelvin was wrong doesn’t mean Present Kelvin is. One of the fundamental assumptions of science as an enterprise is the existence of a Future Kelvin who is correct. The onus of those who cite Past Kelvin to refute a Present Kelvin is to demonstrate that the Present Kelvin is not in fact the long-prophesied Correct Future Kelvin.
I find stargazing such a compelling activity because when you realize we're all already on a spaceship together hurdling through the Milky Way, the sky is a bigger window than anything they have on the Enterprise. You can see a quasar a couple billion light years away with astronomy binoculars. Stars being born, stars exploding, nebulae expanding or coalescing to one day form new stars. One January night my friends and I stayed out for four hours in snow to our shins because a near-Earth asteroid zipped past us so fast, you could see it moving past the background stars in the eyepieces.
Guaranteed, no one who owns a rocket company has looked through a telescope since they were a kid, because when you actually look at the universe, you're compelled to confront your own place in it. You realize being a part of the human society we have down here is pretty much all we have.
I think you overstate the neccesary power of telescopes, seems overly idealistic. I could imagine Bezos or Musk looking through one, thinking "neat", then forgetting about it immediately, or using the experience as part of a speech.
I agree with everything in the article except being “mad about it.” We’re probably the first generation of humans to be offered a fantasy other than the major religion(s) in our place of birth. As alternatives go, fantasy about interstellar travel that inspires us to learn and explore is light years beyond the beliefs that were thrust on all previous generations of humans.
Don't take offense, but your argument is really an argument from ignorance - ie "we don't know how to do this now, so we will never ever be able to do it." Reminds me of people who said in 1900 that heavier-than-air flight was impossible. These arguments rest in part on the idea that we understand physics so well that there are no gaps where we can squeeze in wormholes etc etc. However, there are strong signs that Einstein's spacetime is not the end of the story (and in any case it is very scale limited in explanatory power.) Dark Energy and Dark Matter present gigantic gaps in our knowledge of physics.
I suggest you look into Donald Hoffman's idea that what we call "reality" is not actual reality but merely a "user interface" to reality that evolution gave us to survive & reproduce so that we wouldn't need infinitely powerful brains to handle it all. He calls it "fitness not truth." (He has a TED talk and some other nice videos, but his book "The Case Against Reality" is fantastic.
Hoffman says that we really don't know how many dimensions of space there are. We perceive 3, but that is a simplification. Also we don't know if time is fundamental or emergent from thermodynamics. This leaves open the possibility that we are measuring interstellar distances wrong - the stars could look really far away to our hominin brains that evolved to keep us alive on earth. This might also explain the Fermi paradox - I call this the "wrong radio" hypothesis - not only are we listening on the wrong frequencies but we are on the wrong equipment entirely.
Another source of inspiration here is Kip Thorne's wonderful "Science of Interstellar."
That said incompleteness of our theories doesn’t imply unconstrained freedom Dark matter and dark energy point to gaps in our understanding but they are already tightly constrained by multiple independent observations Any deeper theory has to reproduce those results; they don’t automatically open the door to spacetime shortcuts or radically shorter distances
Okay here's the problem as I see it, and I'm not talking about a science problem. I'm talking about a literary problem. We used to have this awesome genre of fiction where people jumped in boats and sailed off to mysterious unknown continents to meet people who were basically human but completely different from everyone they knew.
Different in interesting and meaningful ways that taught us about the nature of humanity by amplifying certain characteristics. Land of Giants, Land of Gods, Land of Tiny People, whatever. With sea monsters that personified basic forces of nature that everyone was terrified of.
Then we got better ships, and found out what was actually on those mysterious continents, and the frontiers of magic got pushed a little further away each time, until there was no reasonable place we could expect to find magic on Earth.
I think the last example was Erewhon? Where we had to journey to a hidden continent under the Earth to find magic.
Then we got Jules Verne, who entertained the first concept of a space program. Then we got Edgar Rice Burroughs who took the magical continent framework and moved it to Mars. Then our telescopes got too good and there was no magic on Mars, either.
So we had to push the magic back more and more until it required travel to other solar systems, or all the way to other galaxies.
Star Trek is the classic plot of going to an alien place and meeting people who are almost, but not quite like us, so we can explore what makes humans unique in a hundred different ways, by taking certain traits to their extremes and calling them aliens.
But you can't reach the magic aliens without a magic ship, and when the Fermi Paradox started to make us think the whole universe was just an endless series of dead rocks, we came up with time travel twists and alternate universe nonsense that is really just the same misapplication of physics, used in the service of that same old story, meeting people who are almost, but not quite like us.
Or sometimes they literally are us, speculating how our societies would be different if you changed one tiny detail in the river of history.
The magic space warp drive isn't merely a reflection of technological hubris, it's the most elegant solution we could find to a literary problem, where we needed to speculate about the nature of humanity, in a world where we had no mysteries left.
Your answer to why generation ships are impossible are… social issues? I wonder what the kids in the American colonies felt like when they realized they were on a hostile continent thousands of miles away from where their ancestors grew up? The answer is they didn’t really care, because your baseline satisfaction is relative to where you grow up.
Have you considered life extension? If you’re talking about centuries of travel, given the many millions of years (or billions) we have to figure this problem out, you essentially have to be 100% confident this won’t be figured out in a period of time many thousands of times longer than man has had agriculture. Do you think the people building Gobleki Tepe could seriously have predicted the limits of technological development?
Then you bring up Mars, which basically has none of the objections that you just discussed. To make it clear for you, no one intelligent is seriously proposing going to another star system to settle anywhere in our lifetimes. We haven’t even gone back to the moon yet.
Your objections show a lack of imagination, your reasons for caring show a lack of understanding on how space travel improves life here on earth, and your bitterness shows a lack of spirit.
Kids in the American colonies had fresh air to breathe, soil under their feet, blue sky to look up at- you get the idea- real life stuff. It's what humans need. They can't develop properly without it. It's not optional and can only be tweaked so far before a wide variety of consequences begin to sabotage these space workaround ideas.
I swear, you space and sci fi types remind me of the left/woke/trans communities who think they can disregard basic biology and human nature and needs. And it's all just because they want to believe.
Social issues are important to bring up considering that if it takes 1,000 generations to get somewhere, it only takes one generation, or 0.1% to sabotage the mission, refuse to procreate, try to turn the ship around, etc., etc.
Social issues are a reason to expect that it won't be *easy*, but *really hard* and *never, ever happen* are very far apart.
The future is literally trillions of trillions of years (not a few trillion, but much more than a trillion trillions), and we've gone from 98% of the population living a subsistence lifestyle to landing on the moon and having supercomputers in our pocket in less than a thousand years.
Vaguely gesturing at a problem doesn't make something impossible. The author insists on things like "We all think space is roughly a billion times smaller than it actually is" when the "we" are really just people who aren't especially informed or interested in thinking about these things. As if the most obvious objection "Space is really big!" hasn't been thought of by people who like to discuss and think about this stuff often.
The author is a perfect example of the Dunning-Kruger Effect. They know *just* enough to understand that the sci-fi space-opera stuff isn't realistic, but not enough to understand how the most obvious objections have reasonable responses to them. Now there's room for debate on whether interstellar space travel is possible, but a complete novice on the subject coming in and declaring confidently that it's "never, ever possible" only demonstrates ignorance.
First, you're making great points that I agree with entirely. Colonizing Mars is never going to happen. The core is dead; so, it has no magnetic field. Even if you could start producing atmo the surface would be unlivable due to radation. We can try the moon first, but that's also iffy. When we have mastered all the places on Earth -- as you rightly point out -- that at their worst are nothing compared to Mars or space, then maybe we can talk. Mars is worse than the Earth was after being hit by object that killed the dinosaurs. Proof? We're here, aren't we?
I wouldn't mix up "Star Wars" and "Star Trek", though; one is space fantasy with space wizards, and the other tried to eat its own dog food in the form of the science of the time. I'm totally there with you, though. When Data says, "we're 15 minutes from target." Motherfucker! You ain't 15 minutes from shit! Even with warp 10, there's no way you're going to get to a different solar system in 15 minutes! "Star Trek" leaves the distances vague on purpose. They know. But there ARE theories about about how a warp field could be created and maintained; and some experiments have pointed at these theories being possible. It's nothing that is going to happen in the next 1000 years...if ever. We're the same age, Jason; so, I grew up with the same stuff. And I get it. The kid in me is wondering where those warp drives got to too.
Anyway, if you haven't read Adam Becker's book, "More Everything Forever", I recommend it. He talks about this weird "colonize space for the good of the species" stuff and I find his arguments interesting and compelling. Also, he's got a PhD in astrophysics. I kind of think he's got more cred than these other tech douches.
I'm reminded of that great ad with Avery "Captain Sisko" Brooks standing next to the Golden Gate Bridge yelling "Where are the flying cars? I WAS PROMISED FLYING CARS!!!"
Imagine you were transported into the future for just one day. You might want to check out as much future technology as you could, then on your return to the present you would present all those ideas as your own inventions. I suspect that a visitor from the 1950s would be disappointed by today's world. Very little has fundamentally changed.
A generation ship is physically possible, by recycling air, water, etc and growing food. You aren't even denying that. You just don't like it. And would it be cramped? What about a hollowed out, spinning asteroid - that could be fairly large. As for whether future generations hate it - consider a persecuted religious group that is banned on Earth - they might Love a chance to get away and live the way they want to. I'm not saying this would be for everyone - I'm saying that there are groups that would be ok with a generation ship. (Maybe radical. Maybe religious. But that is likely who would sign up for something like this, and like it.) What do you think? Possible?
Note: If you told a human 200 years ago that we would now be routinely manufacturing things like transistors so small you could line up 20 million of them across your thumbnail and that these things would be found in little devices we all carry that can access almost all human knowledge and process 10 to the power of 20 bits of information per second - they might be forgiven for thinking it fantasy.
I enjoyed this article but nearly nothing is impossible.
A GREAT book about a generation ship experiencing a similar scenario to the one you talked about is Aurora by Kim Stanley Robinson. That book convinced me that generation ships are one of the most morally awful things we could do. Great read, do recommend
Another book that explores this in a very reasonable way is The Three Body Problem. I don't want to spoil too much but interstellar travel is portrayed only in terms of generational ships and it is NOT GOOD. Every ship has to be its own fascist nightmare to keep people from rebelling. But the book has this exciting quality because at multiple times in its story, there's a compelling reason for a civilization to embark on a hundreds or thousands-years long journey, and they just do it.
This book also has some things Jason would call magical, but its portrayal to interstellar travel is nothing a nerd would fantasize about.
In The Three Body Problem, the interstellar travelers had suspended animation built into their physiology, and they knew their planet was a death trap. The time scale is right, though.
Not sure if you read *all* the books? :) Avoiding spoilers...
No, hadn't read all the books, but I'm not terribly concerned about spoilers. I tend to enjoy the story more than I enjoy being surprised.
Well for others reading, you've been warned about a big fat SPOILER:
At one point, a few ship's worth of humans barely escape earth and have to form a society en route to a start that's some crazy distance away, hundreds of years, and it's just to refuel. The author does an amazing job of describing how impossibly lonely and dehumanizing space is, like they all lose there innocence at once. There's a brief Mexican standoff over parts, one ship wins, and off they go, as cold, hardened, fascist murderers. It's wild. I highly recommend the whole trilogy, except the first third of book two which could've been a chapter.
Stephenson dealt with it in Seveneves by first rendering Earth uninhabitable for many generations, leaving the space colonies the only way to preserve humanity. But it devolved into mawkish feminist nonsense along the way - women as the literal saviors of humanity because of their superior ways. Not his best book, by far.
I stopped reading Stephenson after that. His early work is amazing. The latest efforts are just Seattle politics.
The difference between old sci fi and modern sci fi is like the difference between old country music and new country music.
Some of the best new country music I hear lately is coming from Shaboozey, Darius Rucker and similar. Same tropes but better melodies. Mostly I listen to country from the 80/90s when I was young and tooling around the western Carolinas in my stick shift ranger.
I’m reading The Mountain in the Sea by Ray Nayler. The first third has me neglecting my clients in favor of reading. Anyone know of similar authors? Or new material in the same vein as Corey or early Stephenson?
Okidoki artichokey...I'll see your Shaboozey & Darius Rucker, and I'll raise ya Lord Huron & Murder By Death:
https://www.youtube.com/watch?v=-TGld4a5Mb4&list=RD-TGld4a5Mb4
https://www.youtube.com/watch?v=EUp97xW9im0&list=RDEUp97xW9im0
I'll even throw in a Hillbilly Moon Explosion, for the low-low-price of FREE!
https://www.youtube.com/watch?v=2rlYPb2plaY&list=RD2rlYPb2plaY
And if you're still not satisfied, may I suggest The Overstory? That's my final offer. Unfortunately I'm not a scifi aficionado, but I think this is your style...
https://www.amazon.com/Overstory-Novel-Richard-Powers-ebook/dp/B073VX7HT4/ref=sr_1_1?dib=eyJ2IjoiMSJ9.1tHnnRSjclPmAqghGpIln8uhykZ4GfG_pzybFE7PDs7ZYc_8zWjeDh37gpL_X8PY2Lk4Nc_SX9udWR55BSb3N94pRPjx_X-DFhCLreBpvaJMfqT8Libi2MYDmIGsFqJt_mryaV6SzlOm6iGm4swWMoq7ZL9KCm22FU-t_QiEFi-EBqYVbUwrygnDBUc7OG0SgfUZHLT79bxtXN2lj_SS_9CpecD7gWC5aHI4uabNdzI.SZNJlQ8r-nJ51icLo2IpjJjs3PIjEFs1K-Q1bnB4foU&dib_tag=se&keywords=overstory&qid=1763601909&sr=8-1
Oh boy, thanks for all those recs. I'm at Costco right now, will reply later. I'll try to think of some suggestions you might like.
You should give his “Polostan” a try. It’s more historical fiction than sci-fi. If you read/like his Baroque Cycle books, this is in the same vein although written in modern language/style.
I did, in fact, love the Baroque Cycle books. I think about them when I eat oranges - with a full set of teeth. 🦷🍊
You could probably read that part as sarcasm, though.
KSR seems to have soured on the peak technological optimism of his Mars trilogy, where "the treatment" extended lifespans by a factor of 3 or 4x. _2312_ posited mysterious problems with long-term life off Earth, and _Aurora_ took this skepticism even further by making the ships ultimately incapable of being a generational human habitat.
IMHO the major failure of the Aurora mission wasn't the ship itself, it was largely intact and functional when it got to Tau Ceti. The problem was the survey of Tau Ceti was incomplete and failed to account for the environmental problems there. The division and reduction of ship resources seemed to be a bigger problem on the return voyage than the ship itself.
I'm not sold on the moral problems of future generations being born on such ships -- no one questions the morality of people being born as immigrants or in difficult environments.
I do think generation ships seem unlikely constructs and extremely difficult engineering problems, but I could see where semi-generational ships (ie, for traveling the Hohmann Transfer from Earth to Neptune and back) could be plausible.
KSR's schtick of using the India (or whatever power resides on the Subcontinent) as a hypercompetent 3rd party that supplants the US/China/Russia/etc is becoming increasingly hilarious in retrospect.
KSR started strong, but rapidly faded.
I still like his more recent stuff, but it doesn’t have the same shine as his 80s and 90s work. The Mars and Three California trilogies were on another level.
From what I recall the ship was breaking down slowly but inevitably - the ecosystems were slowly collapsing and the human population wasn’t having an awesome time either, and unless the planet had been perfect the situation would have always been dire. Whether ecosystem collapse on a generation ship is inevitable is anyone’s guess (though the biosphere projects don’t fill me with confidence), but to throw people into a 160-year-long journey without knowing whether their ship could actually last that long and without any capacity to make it back seems like a pretty raw deal.
I think people definitely question the morality of having kids in difficult environments. It’d probably be morally wrong to decide to have a kid in the midst of a famine or something like that, where the kid’s predominant experience of life would be some sort of suffering. I’d say that a generation ship gone-or-going wrong is pretty comparable to those circumstances, probably a morally bad place to have a kid.
If we HAVE to try interstellar travel, I think that some sort of relay system or set of stepping stone stations could be good - something where there’s a way back or at least a way to some sort of safety if people decide they don’t want to continue the mission.
> but to throw people into a 160-year-long journey without knowing whether their ship could actually last that long and without any capacity to make it back seems like a pretty raw deal.
So basically every Atlantic or Pacific crossing until the 20th century? Long voyage loss rates were 3-5%. As many as 5% of overland migrants (aka "pioneers") died in transit.
I just can't help but think such thinking reflects a risk-averse mindset biased by relatively recent technology which makes long distance travel very low risk. Long distance travel has *always* been high risk, even on land (war, bandits, weather, poor maps, harsh geography).
Kids turn up frequently in the worst places where you wouldn't think people would be eager to have kids (Gaza, civil-war Syria, famine/war plagued countries). I think for better or for worse, human reproduction is driven by hormone-fueled neurobiology which defies rational thinking, otherwise we might have died out early as a species.
That being said, dumping people into a tin can for 12 light years and just hoping it all works out is dumb, and I'd agree that stepping stones make sense. Though I think there's limited value in building stepping stones past the heliopause. It's not like you could easily "just stop" at a space outpost (killing all your delta-V) 3 light years into your journey to Tau Ceti. Plus if you're into the moral trade-offs of long space voyages, who's gotta go live at the "last stop before Tau Ceti" interstellar space station?
IMHO splitting the ship's assets and people in half (even with their dues ex machina 3D printer) at Tau Ceti was the error. In the Tau Ceti system they had access to a lot of raw materials and probably could have just lived in a greatly expanded space station, possibly long enough to solve the biological problem they ran into on the surface. If they HAD to go back, they should have stuck around long enough to reconstitute the Aurora's original scale before departing.
😂 Thank you!!
That book does demonstrate this but in a very silly and hypocritical way where the only characters in the story who actually do the morally awful thing in question are the heroes. Which could have been an interesting twist if the author genuinely cared about the moral implications, especially since the heroine abandons half her population to die on a toxic planet in order to fund the voyage. Instead KSR introduces stasis pods via deus ex machina, letting his heroine skip back to earth to righteously condemn a new generation of prospective space travellers for a crime that they, unlike her, were not going to commit.
Came to the comments specifically to recommend this book. It dramatizes most of the problems you talk about & a number of ones you don't (I shan't spoil them, read the book!). It's quite superb, highly recommended
I heard KSR say (at one of his annual appearances at the Bar Harbor library) that while he was writing Aurora he came to realize how impossible generational space flight would be, but he went ahead and finished the book anyway. It gives us something to talk about.
I wouldn't treat Aurora as gospel. Didn't they literally invent the suspended animation technology that would make interstellar colonization possible at the end?
I may have read other speculative fiction on this subject, so if the following points are not addressed in Aurora, sue me.
What I remember is even if you stipulate suspended animation working perfectly, you still have the problem of small or large degradations of the entire ship to worry about. How many spare parts and repair kits do you plan on bringing? Or do we need to also stipulate nanobots and replicators?
Then there is the micro-organism problem. We evolved for Earth environments alongside of all the other life forms here. Starting over in another environment that is basically similar to ours leads to “is basically similar ever going to be good enough, or will be wearing space suits forever?”
https://dasha016.substack.com/p/sci-fi-novel-chapter-2?utm_source=share&utm_medium=android&r=8ojt06
New chapters of A novel
A wonderful book that explores all of this in detail specifically the Moon and MARS, ignoring the interstellar travel issue, it’s called A City on Mars. https://share.google/pexeKygAga1Cp6yLP
I came into the comments to recommend this book! So fantastic
The OG of "generation ship" stories is "Orphans of the Sky" by Robert Heinlein. Originally two novellas published in 1941, was later put together into one novel.
Also, Hull Zero Three
And this is the simple answer to the Fermi Paradox. Everything is much harder than we make it out to be. Including not destroying your own planet/civilization on the way once technological progress advances enough to make spaceflight possible.
Interstellar travel is hard, but communication is not. Interstellar communication is something we could easily do now, much cheaper than any given space probe mission. And our next generation of space telescopes will be able to identify planets like earth, so anybody out there should know our planet has life, and could have for a very long time. Yet nobody's pinging us.
It took more than 4 billion years for earth life to develop interstellar communication. It took 300,000 years after our species evolved. There is no guarantee that any of the evolutionary steps, as well as the many contingent technological requirements like fossil fuels, or smelting, would arise (noting that literally not all humans had developed these). It's an assumption on your part, and the part of many, that such communication is easy, which is not born out either by our history, nor the silence of the universe. I believe that assumption is flatly wrong.
Yes, there are lots of steps in the paradox that could be very unlikely. It's just that difficulty of interstellar communication as a technology is not one of them, so the difficulty of interstellar travel is not a bottleneck.
Communication between stars using relatively inexpensive radio dishes, or short pulse lasers with ground based telescopes, is feasible for us now. There's just nobody on the other end to talk to.
Just because it's feasible for us does not mean it's feasible or easy for other creatures. An intelligent species that evolved in the oceans of a water planet would never have any need for such a thing. They might never even conceive of it. The universe could be filled with super-whales, and we'd have no way of knowing, and they'd have no way of letting us know.
As I estimated in anohter reply the recipients of such a message, should they exist are more than ten thousand light years away. So why would you expect a response?
But your estimates are wild guesses at the pessimistic end. The "fermi paradox" is about aliens not being obvious. Well, just assuming colonization is very difficult solves that. Then you just need to explain them not building omnidirectional beacons, or pinging millions of stars one at a time very often. That's not hard to explain: beacons are very expensive, and a serial ping program might take a long time for us to detect, or be something only new young civs engage in.
I...can't help but think we're advertising plenty as it is, and while it's reasonable that most hypothetical Things won't notice...I think there are some invalid assumptions baked into the cake of your premise. To lay flat your assumption set as I see it 1) like us enough to understand the message received 2) advanced enough to receive and parse the message, and 3) not wanting to eat my face out of spite or maybe other reasons. Maybe no. 3 is a bit much--quite a long drive just to eat my face--but the first two seem to me like a math problem with several major unknowns.
We've been broadcasting for maybe 80 years, so given return signal time they'd have to be within 40 light years. That's a few thousand stars, out of around 100 billion in the galaxy. So unless civilizations that could reply it are common as dirt, we wouldn't expect to be detected by now. We might have received a very strong and active broadcast that was just ongoing for millions of years, but haven't yet.
So it seems like we can rule out extremely close civs that are chatty, as well as very high-resource long-duration broadcast programs (ongoing for millions of years to find new civs like us, broadcasting constantly to millions of stars). We would miss civs that listened for leakage radio first but are more distant than very close by, or civs that had broadcast programs that were patient and expected us to do a lot more work or didn't mind it taking millennia for us to happen to hear their ping. Basically we have covered almost none of the search space.
Also please correct my non expert ass but space is much bigger and deeper than any Earth ocean so if I’m 99.99% unlikely to spot say a submarine that’s near the ocean floor, even if i have a super effective scope—how much less of a chance that I’ll pick up an alien signal that i can parse?
Seems like a great thread for book recommendations.
Simple calculation. We've found around 5000 exoplanets, none of which are remotely like Earth. Assume that the probability of a sufficiently Earth-like planet that could evolve life is 1 in 10,000.
One Earth multicellular live first arose around 600 million years ago. From that organisms capable of receiving and transmitting extraplanetary EM radiation in the radio region of the spectrum has existed for about 100 years or about 1/6 millionths of time. Combine this with the 1/10000 frequency for Earthlike planets and you get 1 in 60 billion stars have planets. Given the 0.14 stars per cubic parsec density of stars in the Milky War we need a sphere of diameter 11,700 parsecs (38K light years) to contain two civilizations capable of sending and receiving EM messages. The other advanced civilization is tens of thousands of light year away, By the time they detect our signal (should be ever send one) we will no longer be anything like what we were when that signal went out.
Google AI says the Milky Way is at least 100k light years in diameter so your math suggests at least several civilizations here at home. Then there are 2 trillion galaxies!
Other galaxies are hundreds of millions to billions of years away travel time and so irrelevant. Even the few in our galaxy are millions of years away, still irrelevant.
Counterpoint: wormholes
Counter-counterpoint: If wormholes exist and can effectively be used for travel or communication, then you’re back to having to explain Fermi’s Paradox.
No reason to believe such things exist.
This is key — as it stands noone knows one way or the other.
Broadcasting may be easy, communication not so much. A two-way “chat” with the nearest star would involve 8 year gaps between messages.
There is a quality of subatomic particles called spin that could perhaps solve this problem - change the spin of a lepton and it's pair responds with changed spin instantaneously regardless of distance - but even ignoring the considerable practical difficulties involved in creating a usable communication device based on subatomic particles it still leaves the problem of needing two paired devices - transmitter/receivers, one of which would still need to be sent to the destination.
Long waits between pen pal messages seems like something we can handle. Space probes already have long timelines: the Europa clipper mission began work in 2013, launched in 2024, won't arrive until 2030 and then runs for 4 years. The voyager 1 probe was launched in 1977, and is still in contact and returning results.
That exact thing is a major plot point at the end of the novel “Star’s Reach” by John Michael Greer. It’s revealed that interstellar travel is physically impossible, but interstellar communication is possible and prevalent throughout the universe.
The closest star is 4.2 light years away. What do you think that fact means in the context of any kind of radio communication?
That it takes patience, probably more than we have now. It would likely take centuries just for two civs to find each other by radio survey. But we already do long projects: Voyager 1 is still in contact and has been in flight for 48 years. The ESA jupiter moons mission took 12 years to design and build, and will take 8 years from launch to get there.
Civilisation will probably be destroyed because no-one worked out how to train their dragon before someone genetically engineered a dragon...
The false assumption behind the Fermi Paradox is that any civilization will expand indefinitely to master any conceivable environment, except the only species we know to exist doesn’t do that. Look at that satellite photo of Earth from space. Note that it doesn’t look like Coruscant: most of Earth is uninhabited. Not just the oceans either—huge swaths of land are uninhabited. The western United States between the Great Plains and the West Coast is largely uninhabited. It’s got arable land, fresh water, a reasonably decent climate, and is part of the most prosperous society in human history, yet despite this, relatively few people are willing to try to make a go of it in Wyoming.
Or consider Antarctica: not one single person in all of human history has attempted to raise a family there. There is a whole continent on this planet with breathable air, abundant water (or at least h2o), radiation shielding, normal gravity, normal air pressure, etc where literally zero human beings out of 100,000,000,000 have lived the first five years of their lives.
While it’s true that life writ large has a remarkable tendency to adapt to survive in any environmental niche, individual species rarely stray very far from the environments in which they’ve evolved to survive. The nearest planet with anywhere on it as hospitable to human life as Antarctica has yet to be discovered, but even if it turned out to be reachable in a single human lifetime, we know with a high degree of certainty that no human being will never attempt to colonize it, because no one has ever attempted to colonize the Antarctica-like part of Earth that can be reached within a day or two.
Your comment touches on a very important point, and a problem which the reification of astrophysics has, in my opinion, directly contributed to: a disregard for earth's uniqueness. It's extremely easy to live on earth for an ape with the biological needs of a chimp, but triple the brain capacity. Most of the problems we face are caused by ourselves, not by our environment. Even our most inhospitable environments are absolute paradises compared to everywhere else we've observed so far. I think there may be specific reasons for that related to planetary evolution, but whether it's very common or exceedingly rare, the fact is that it doesn't appear easy to reach such a place.
By implying that space is easy or even possible to colonize, whether terraforming Mars or long-distance travel to more suitable planets, it causes people to disregard how important and special our planet actually is.
I agree.
So here is my take on the Fermi paradox - let’s say that an alien civilization lasted 10 million years (an incredibly long time by our metrics). Their electro magnetic signal streams past earth for that long - a tiny fraction of earth’s history. The odds of it overlapping with our time as an advanced species capable of identifying and analyzing it would be related to how long we survive in that state. Half a million years looks pretty ambitious at this stage, so the odds of any intelligent life seeing any other intelligent life get pretty slim, even if they do exist for some pretty long timeframes. So maybe that’s the ultimate irony - distance and time make the chances of overlapping pretty poor. Even if we do detect another intelligent civilization, the further away it is the less likely it is to still be present when we detect it, much less by the time anything we try to Send back to them gets there. We would be looking for and trying to talk to ghosts. The obvious solution would seem to be that advanced civilizations don’t last very long even if they do arise with some frequency and that makes them nearly impossible to detect in the tiny sliver of time we have been advanced enough to look for them.
Not really. There is no bar on unmanned spaceships. It takes only one million years for a civilization to spread its unmanned spaceships over the entire galaxy so the unmanned ships should be here.
The bars are literally resources (relatively few) and incentives (none).
Gene Roddenberry was dead wrong! Every space faring civilization will have accountants! Lots of accountants!
If the probes travel at relativistic speed, it doesn't take them hundreds of thousands of years.
I think that an easier answer to the Fermi Paradox is that we don't know what to look for. Radio transmissions started a century ago, and we've already found lower energy ways to do those transmissions. It might be that we won't even need to use radar to track air traffic in another hundred years. What will be left for other aliens to watch for? Two hundred years is a drop in the bucket in terms of visibility.
In the other direction, it would be easy to believe that fusion rockets are propelling intelligent life all over the galaxy. We wouldn't see their exhausts unless the rockets were pointed right at us. If they were pointed right at us, what would they look like? Quasars, that's what. (The reality of that theory is that half of them would be blue shifted, but it illustrates that we don't even know what we're looking for.)
Even if you assume an average rate of expansion of 100 years/ly (0.01c, likely achievable with Orion drive), you could still colonize the entire galaxy in 10 million years (blink of an eye in astronomical terms). I don't think the difficulty of interstellar colonization is necessarily a good Fermi paradox solution
Yeah, if you assume stuff that has never happened and hasn't proved possible you can do anything.
My point is, we have no reason to believe that interstellar colonization is a severe Fermi Paradox barrier for an intelligent, technologically advanced species. Based on what we know about physics, it should be possible to colonize a galaxy in a relatively short period of time, astronomically speaking.
The universe has likely been able to support intelligent life for at least a billion years before it emerged on Earth. If an alien civilization in our galaxy had developed spaceflight 10-100 million years ago, it should have expanded to detectable levels by now based on what we believe to be feasible under even our current, limited understanding of physics.
There may be other reasons that interstellar colonization is infeasible, but I dont think it's an assumption we should default to just because it would be infeasible to us right now, when we've barely even explored our own solar system.
We have hundreds if not thousands of reasons. You're just ignoring them.
You need to disabuse yourself of the idea of an “M-class planet”. That is the second biggest fantasy Star Trek indulges in to sustain its premise. Everything we know about biological evolution and astronomy suggests that interstellar colonization is impossible. Organisms tend not to survive outside of the environments in which they’ve adapted. So for interstellar colonization to be possible, a species would need a second planet nearby with conditions similar enough to its home planet that establishing colonies there would be a worthwhile endeavor. Finding even one such planet nearby is wildly improbable, let alone a whole network of them, each close enough to the next that the species could expand indefinitely.
I understand that there are no “M-class” planets. Any habitable planets in the galaxy other than Earth will only exist due to terraforming. However, I don’t think planets will be all that important to human civilization in the distant future. Eventually, I would expect most people to live in O’Neil cylinders for the simple reason that a Dyson swarm of such habitats could support a population may orders of magnitude higher than Earth alone. In any case, I agree that we’re not going to find any habitable planets through interstellar colonization.
Why would anyone terraform a planet? Why would anyone build a Dyson sphere/swarm? They’re both fantastically expensive undertakings. A civilization capable of doing either is capable of improving Earth to the point that they’re unnecessary. Consider that it’s within the realm of technological possibility right now to build a permanent habitat on the moon. But how many people would want to raise children in the kinds of permanent moon habitats we could build now?
The reason space or extraterrestrial colonization will never happen is that there will always be a huge gap between the lifestyle a society can provide on Earth and the lifestyle it can provide to dwellers of the colony, and no one will choose the colony over Earth, especially not for their children.
Carrying capacity. You can only improve the Earth so much before you reach a hard limit on the population it can support. While we're currently seeing declining birth rates, that won't continue indefinitely. There will always be groups in society that reproduce at high rates, like Mormons and Amish, and these will tend to increase as a proportion of the population over time, increasing overall birth rates. In the long run, we should expect the population to increase to whatever level can be supported. When that happens, we may resort to population control, but not everyone will want to limit their family sizes. At that point, only place to go is up and out. Of course, by the time we reach planetary carrying capacity, it would likely be trivial to build rather comfortable space habitats due to technology and orbital infrastructure. As for the expense of building space habitats, they get cheaper in relative terms as a) the amount of orbital infrastructure increases and b) the amount of energy available to civilization increases.
If we have enough surplus to build habitats in space that can house nontrivial numbers of people, then by definition there’s no problem with our carrying capacity. Carrying capacity is a function of the amount of available resources
The intrepid crew of the Enterprise rarley needed helmets to land on a new planet.
Oh, how I wish that it was true.
I think mechanical aliens could do it.
https://jasonpargin.substack.com/p/interstellar-space-travel-will-never/comment/179713353
For that to answer the Fermi paradox, don’t you also have to assert that self replicating probes are completely impossible at any level of technology?
Not an insane assertion, but still a disputable one.
Not impossible, necessarily, but I do think it's far harder than sci-fi makes it out to be. And I think that's because a lot of sci-fi is written by people with some understanding of astrophysics, and maybe adjacent fields, and comparatively little about sociology, biology and geology, the stuff of life and natural resources.
But more importantly, I think it's unlikely a rational, self-interested society would ever create such a thing. It's a massive investment, and to what end? Why would I ever work on such a project? Is that feeding my family? Is that saving my planet?
And I have no problem with such Von Neumann machines as a sci-fi trope. It helps us think about the problem, which is a great thing. The problem I have is when ignorant people take fiction as proof that something is possible or even likely. I assert that it may not be possible, but is definitely exceedingly unlikely. And the evidence is both our society, and also the absence of others.
It is not. We should be seeing evidence of advanced civilizations even if long-range space travel remains essentially impossible.
Came here to say this
We are (among whichever others exist) universal nerve endings. What we imagine is possible, unless, that is, system’s theory arrives to cull the outreach. That said, I do believe barriers are there to be broken (just not in the Trump/Musk/authoritarian/ technofeudalism sense – among others)
We would not recognize extraterrestrial life anyway, much less intelligent extraterrestrial life. Our concepts of life and intelligence are determined by our earthly existence. We might not even be able to sense them at all if we encountered some.
The bloody obvious solution to the Fermi paradox is that there are no other civilizations in the universe. Why do people always assume the case unsupported by any evidence whatsoever then try to rationalize it?
So why are there no other civilizations? The answer to the paradox is not as easy as you make out. Where along the line of development did other potential civilizations stop? We don't have "proof" that life is likely or unlikely. We don't know how many planets in the galaxy are capable of evolving life, or to what degree. Nor do we understand what encourages or discourages it from attaining sufficient complexity to exhibit eusociality, language, self-awareness, tool use, science, etc.
The answer to these questions, which makes them relevant to this discussion, probably *requires* interstellar travel, or comparable power and technological complexity—say, for building very large and detailed simulations.
Nobody's saying (well, probably some are) that there are no other civilizations. They're saying there are no other civilizations that can travel to visit for Thanksgiving dinner, or Earth Day, or....at all. The laws of physics are what are keeping us all in our lanes, so to speak, and the sooner we accept that the better (know how many people could have homes, and nutrition, and educations, and families, and futures, on the money Musk is wasting on launching to Mars--or, rather, preparing the infrastructure to launch a necessarily-doomed expedition to Mars to 'pursue man's destiny?'). Why do we always have to learn the hard way?
Re: Musk. The money is being spent on earth. There is nowhere else to spend it.
I think Mars is reachable, just barely. But Mars is the end of the line There is nowhere else to go.
Hm. How many invalid assumptions--as there would no doubt be several--would it take to make this "large and detailed simulation" a fever dream that either leads us nowhere, or leads us astray? Asking for a descendant. To be more fair--what assumption sets must we necessarily accept or reject when attempting to create these simulations, if that's the way? (You can not believe me when I say so, but I think myself to be agnostic and want to explore the idea.)
Time is long.
Space is large.
Civilisations are short.
Inverse square laws suck.
Mix and match the above until you find the Fermi Paradox answer you like.
Inverse square laws are Dream Killers.
People think it's a mystery because
1) The universe is really, really, really big. *Really* big. Even if we restrict ourselves to our galaxy.
2) Life on earth emerged remarkably quickly, basically as soon as the lava cooled.
Expanding on your second point reveals the answer to the Fermi Paradox. We can make some inferences about how likely it is that life evolved elsewhere from how quickly it evolved here. Assume that on any Earth-like planet, life will inevitably evolve there on approximately the same schedule as it did on Earth. (This is a wildly optimistic assumption) That suggests that the fraction of Earth-like planets with intelligent life is equal to the percentage of Earth’s total lifetime it was host to an intelligent species. So we should expect 0.0004% of Earth-like planets to host intelligent life. Now, intelligent life has existed on Earth for 200,000 years, but it’s only in the last 100 or so that we’ve been sending detectable signals. So we can estimate that only .05% of intelligent life that exists is even detectable. Overall that gives us 1 theoretically detectable civilization for every 45 million Earth-like planets.
Now assume every star is home to an Earth-like planet (another wildly optimistic assumption). The average density of stars in our immediate neighborhood is 1 per 16 cubic light years. 16 * 45 million is 720 million. The cube root of 720 million is about 900. In other words, in the face of two wildly optimistic assumptions, we should still expect that the nearest detectable intelligent civilization is at least 900 light years away.
The fundamental assumption of the Fermi Paradox is that there’s nothing special about Earth. But following that logic to its conclusion suggests that we shouldn’t see any signs of other intelligent life, not that signs of it should be everywhere. In order for there to be abundant intelligent life in the galaxy, there must be some way in which Earth is unusual. We can our own planet’s history as baseline assumptions for values of the Drake equation and toggle which ones we need to to figure out which parameters need to be different and by how much to have a reasonable expectation of other civilizations.
The exceptionally large moon is special to earth.
Yes, but it is likely life got started from tides from the moon. How often do other earths get a moon? Not many.
Dude, there are many more oddities than that. There's good evidence that you don't get our biospherical complexity unless you have a strong magnetic field. How many planets do you think get hit by another planet early in their development, creating our dense, radioactive core? Based on the heavy metal mix, our system was created from dust that had been through at least two previous cycles of supernovas, and that limits how early in the universe's history a life-bearing planet could come into existence.
The super-easy answer to the Fermi Paradox is that we are totally guessing at the components of the Drake equation.
"How many planets do you think . . ." One out of eight by confirmed observation.
That’s a powerful point. Occam’s Razor says that “no super high tech civilizations” is the simplest and hence preferable explanation.
The Universe is Pretty Big. If civilization can happen once, it can happen many times.
That's really a better way to look at it. The odds of intelligent life coming about exactly once is essentially none.
No argument. I have no doubt there are thousands, millions of civilizations of every shape size and intelligence out there. Much of this discussion, though, is about us all getting together for picnics and music festivals and concerts with blue-tubed divas. That ain't happening
I saw 'The Blue-Tubed Divas' open for 'The Who' in 1988.
We expect this because the formative years of science fiction happened when they did.
In the 1950s, jets were new, and rockets were about to go into space.
In the early 1900s, powered flight was new.
In the 1850s, steam trains and boats were massively increasing transport options.
In the 1800s, practical steam engines were new.
In the 1750s you had horses and sails, just like the Babylonians.
Someone writing SF in its early years extrapolating forward would reasonably expect transport tech to keep going on this trajectory.
Similarly, in the early years of SF colonial and explorer-based fiction were still popular and unexamined, but the frontiers where it applied were closing or closed. So move the setting to space.
So we get super-fast space vehicles exploring and colonizing outer space.
As a tradition.
this is the only sociologically intelligent comment
I wonder what future sci fi authors will extrapolate from what we have become?
I wonder what future sci fi authors will extrapolate from what we have become?
Let's talk about the physics, because there are some very common mistakes people make.
Let's suppose we could propel a space ship at .9999c. It's obviously a futuristic goal, but it's not Harry Potter. We already propel things orders of magnitude faster than that at CERN. Let's suppose we're not bothering with the closest stars. Let's say we're going to Vega, which is about 30ly away. People who haven't studied relativity sometimes mistakenly think that the trip has to take at least 30 years, but in the "proper time" for the people making the trip it would actually take only 49 days. (For anything traveling the full speed of light, the "proper time" travel time for any distance is zero.) 49 days is significantly faster than the first human trip to Mars will take. However, for the observers home on Earth it will appear to take 30 years for the trip and another 30 years to get the signal back showing the landing. That shows that yes, if interstellar travel happens, it will likely be for colonization, not exploration.
A grain of sand traveling at .9999c would indeed have the kinetic energy of a small nuclear explosion (a grain of sand at .1c would only have about the energy of a 1 ton vehicle travelling 100 MPH), but particles that large in interstellar space would be extraordinarily unlikely to be run into. Micron dust yes, but that's more manageable.
The biggest challenges are propulsion, fuel, and shielding. For propulsion let's say we could achieve and sustain indefinitely 1g of acceleration. It's obviously a futuristic goal, but it's not Harry Potter. We very reliably achieve more thrust in spacecraft and haven't been doing it for that long. The problem is the fuel and the efficiency, not the physics. If we could sustain accelerating 1g acceleration half way to Vega, then turn around and decelerate at 1g the second half of the way, we'd have peak v of around .9999c, and the total trip would take 6.6 years. (Link to math below.) Still very reasonable for colonizing Vega.
For efficiency we'll want to assume we have antimatter fuel and a propulsion system that can use it, because that's the only way to have a storage mass to energy ratio which makes it plausible. Obviously a futuristic technology, but not one that defies physics.
As to the question of why we'd go, it depends on the time frame. The sun will not last forever. Once it starts transitioning to a Red Giant, survival on Earth will eventually become impossible as a matter of physics, not as a matter of technology.
But it gets even more interesting to apply the same reasoning for much larger distances. The Andromeda galaxy is 2,000,000 light years away. Using the method of 1g half way there then decelerating 1g the other half way, we'd peak at around 0.9999999999c, and it would take us 28 years to get there. On our trip to Vega, the cosmic background radiation became "blue-shifted" into a red hot disk in front of us, but at the speed we'd reach going to Andromeda, it would become much much much hotter. The view of the cosmic background radiation and of andromeda in front of us would be compressed into a microscopic spot. The light from andromeda would become X-rays/Gamma rays with the energy flux comparable to sunlight, and the cosmic background radiation's would be UV or X-ray with an energy flux with a couple hundred times the energy flux of sunlight. This creates two interesting questions. First how do you shield it so the spacecraft isn't instantly vaporized, but second, what if you could capture that energy and use it for propulsion so that that problem actually solves the problem of the absurd amount of antimatter fuel you would need for such a trip, because once you get to a certain critical speed, you can use the blue-shifted cosmic background radiation as your energy source instead of stored fuel. Is this a physics problem or a technology problem? Less clear, but it's at least plausible that making the 28 year trip to the Andromeda galaxy is just a technology problem. Of course if you're going to signal back home that you've arrived, it will take 4 million years for the message to get back, so everything about this trip is definitely one-way.
Most of the math in this is at this link, which is one of the best static pages that's been on the Internet in one form or another for almost 30 years:
https://www.desy.de/user/projects/Physics/Relativity/SR/rocket.html
I can't say how much I would love for there to be some movie (or a book) involving interstellar travel using this actual relativistic physics.
I'm very surprised that this is the first comment I've found that mentions time dilation.
This is also why, after a certain scale, interstellar travel can only ever make sense for conscious beings and never for probes. No Earthling will ever send a probe to Andromeda, because physics flatly prohibits ever getting a message back to Earth in less than 4 million years. But physics doesn't prohibit a traveler going at relativistic speeds getting there in their lifetime.
Relativistic speeds are practically impossible. At such speeds every hydrogen atom the ship encounters will collide with the impact of a cosmic ray. The required shielding would be immense and would further increase the fuel requirements. The shielding-fuel conflict means we practically cannot get much faster than a third of the speed of light.
Cosmic rays aren't so bad. A hydrogen atom travelling at .9999c has a tiny amount of energy. A ten millionth of a Joule. I don't think there are enough of them in interstellar space to be an issue.
The Bussard ramjet that was used in a lot of sf in the 60s became impractical when better data on interstellar hydrogen became available.
Coincidentally or serendipitously, I'm writing a novel about a colonist mission to the planet of another star. Your comments have been of great help. Why it's taking me so long: there is so much science to be studied. Compared to cytology, rocket science is like Lego! Also as I age, my math skills are steadily departing. Wrongly or rightly, ignoring relativity, I calculate acceleration times as follows:
Speed of light: 300,000 kilometres per second, or 300,000,000 metres per second.
Acceleration of 1g: 9.81 metres per second squared.
Time to speed of light: 300,000,000/9.81/60/60/24: 354 days
If Vega is 28 light years distant, the ship would accelerate and decelerate for 1 year each, and coast for 26.
(My ship the Cygnus travels at Vmax 0.4c as that is the most that the space debris pulverizing systems can handle.)
Google AI overview tells me that upon annihilating with matter, one kilogram of antimatter releases 1.8 x 10^17 joules of energy. That's quite a lot. Naturally, the ship would also have to carry the matter to be annihilated with. I'm not very happy with my reasoning here; please will you help me out?
Mass of spaceship: 1000 tonnes or 1,000,000 kilograms
(Yes it can be done, even with present-day carbon fiber, never mind what new materials will be available in the future.)
Joules to accelerate 1kg by 1m/s² : 1
Joules to accelerate 1.000,000 kilograms by 1m/s² : 1,000,000
Joules to accelerate 1,000,000 kilograms by 300,000,000 m/s² : 3E+14
Which is well under the Google number. But it's such a small quantity that I'm just a wee bit skeptical. Help!
Aw, my book is frozen-man generational ship combo. It’s got mammoths, though .
Unfortunately, with relativity the math is a little more complicated than that. Fortunately, AI is very good at it. If you ask either Google AI or ChatGPT 5 "Using relativity, and 1g acceleration, what's the time and energy consumption required to accelerate 1000 tons to .4c?" It looks like they both use the right formulas, and the right steps, and get to the same answer, though ChatGPT 5 provides a lot more detail, namely to reach that speed:
154 days according to Earth
150 days according to the ship
8E+21 Joules needed
Thanks, I can't remember where I got it but I used the 1/(sqrt(1-(v²/c²))) formula to calculate the energy curve. Days are close, joules wayyy out but the fuel load is still manageable.
Once you're cruising at .4c, though, if you've stopped accelerating, the rest of the math is easy. Your Lorentz factor at that speed is .9165, so your distance to your destination is 8.35% shorter than it would be if you were at rest because of relativistic length contraction. So the time to get to your destination while cruising at .4c is just the distance from the ship to the destination reduced by that 8.35% divided by .4c. Relativity helps you get there faster.
There a non-conscious beings that aren't simple "probes" that it may be of interest to send. For example, ships designed to replicate themselves, find other alien species, and uplift/guide them.
We would not, under any circumstances, want to uplift/guide any intelligent lifeforms. All that does is create competition for what would be, under geologic timescales, finite resources. It's retarded to even contemplate. What we would want to do is either A) Wipe them out or B) Leave them better. Option B is the kind, merciful option but under the caveat that we wouldn't be expecting them to get into space on their own. Otherwise Option A is the realistic option
That is just re-stating the problem with a different description of Harry Potter’s wand. How to accelerate a large ship to .9999c - and decelerate to land? An ocean liner carries people for a week, no cargo for colonization or spare parts for a long voyage, tiny engines, and small fuel tanks. A colonizing starship would be far larger. Its fuel and boost mass requirements would be larger than gigantic.
Fast boosts over interstellar distances are beyond any technology we can imagine (ie, they’re magic). Many people have explained this. Perhaps most clearly is Jerry Pournell in “Those Pesky Belters and Their Torchships” - Galaxy, May 1974. In brief, it requires mind-blowing massive long-duration power source and even larger stores of boost mass.
It has been frequently reprinted. Here is the text:
https://archive.org/details/Galaxy_v35n05_1974-05/page/n107/mode/2up
And the fact that Pournelle is pointing out correctly that it's all about the energy requirements brings to mind Nikolai Kardashev, and the Kardashev Scale which describes a "Type 1" civilization as one that can store and consume all of its planet's energy, and a "Type 2" civilization as one that can store and consume all of its star's energy. Type 2 technology is close to unimaginable, but if a Type 2 civilization ever existed, then it follows that interstellar travel would be trivial for it, since it's the storing and using of energy on that scale that is the main issue.
Exactly. But we could as easily say a Type 2 civilization unlocks the power of magic. Just because we can imagine it, does not mean it is possible.
As every investment in the US says, “past performance does not guarantee future performance.”
With the same logic though there must be things that are possible that we can't imagine yet.
Pournelle is pointing out the implausibility of mining asteroids with *near-future* technology. The trip to Vega would be impossible with near-future technology, no question. But it could be done with plausible-according-to-physics technology. What Pournelle is pointing out is the energy constraints, which is definitely the biggest barrier. What we'd have to do is crazy by modern technology, but unlike Harry Potter, we can write all the physics equations for how we'd do it. The technological steps we'd need are:
1) Convert a massive amount of energy from the sun into matter/antimatter fuel. There's no existing tech for it, so it's far-future, but there's no reason in physics why we couldn't do it.
2) Invent a way to store large amounts of antimatter. Again, far future tech, but we already do it at small scales at CERN.
3) Store one ton of that fuel (886 kg, calculation from the link in my post) in a spacecraft for the Vega trip.
4) Develop a propulsion engine that can convert matter/anti-matter fuel into 1g of propulsion. No existing tech like that for sure, but you can easily write the physics equations for how it could conceivably work.
That’s a narrow reading of what Pournelle says.
1/ First, he is not focusing on asteroid mining - but on propulsion systems.
2/ You mention only one of the two constraints Pournelle discusses. The second is boost mass. To accelerate to relativistic speeds and then deaccelerate would require a bizarre load of both fuel and boost mass. A crude analogy would be a coal burning (steam engine) cargo ship capable of circumnavigating the world.
3/ Stating the energy required for a trip to Vega is not useful, without mention the weight of the ship (excluding mass for fuel and boost) and duration of the trip (by the ship’s clocks).
Yes, sorry I misread what the chart was showing. It's 1 ton of fuel per kg of payload for a Vega trip. So it would be many tons. Again, wild to imagine, but not magic in the sense of being contrary to physics.
That seems reasonable. For what duration trip to Vega? That makes a difference when calculating payload. Supplies for a day or a year or 10? Also, what boost mass is needed (that is, what efficiency of the drive)?
Also, what is its radiation shielding? Massive ice or metal in front?
If the ship, loaded, is like the Nimitz (~100k tons + 100 tons antimatter + boost mass + fuel & boost mass for the boost mass) - that would be quite a starship.
As you said, it would not violate our laws of physics. The author’s comparison to magic was, I believe, a literary exaggeration. Such a ship is so far from our tech as to require multiple tech revolutions. I doubt we can even imagine the nature of a society so far in the future, with such advanced tech. Hogsworth’s magic world is as good a model as the usual sci fi world.
That’s a narrow reading of what Pournelle says.
1/ First, he is not focusing on asteroid mining - but on propulsion systems.
2/ You mention only one of the two constraints Pournelle discusses. The second is boost mass. To accelerate to relativistic speeds and then deaccelerate would require a bizarre load of both fuel and boost mass. A crude analogy would be a coal burning (steam engine) cargo ship capable of circumnavigating the world: 99.999% of its weight would be coal.
3/ Stating the energy required for a trip to Vega is not useful without mention the size of the ship (excluding weight of fuel and boost mass) and duration of the trip (by the ship’s clocks).
"I can't say how much I would love for there to be some movie (or a book) involving interstellar travel using this actual relativistic physics."
There are lots of books. One to try might be Poul Anderson's Tau Zero.
"The Forever War" deals with dilation as it affects military conflict. It begins in 1997; by the time the narrator returns from a series of ever-deeper sorties it's thousands of years in the future. Human society is unrecognizable, and the conflict has long been settled — not by battle but by the parties being able to communicate the misunderstanding that led to carnage. Staging points from which the human forces departed have staff only from a sense of obligation to those who had launched from them.
"What are we fighting for? Don't ask me, I don't give a damn!"
- Country Joe McDonald
Another is Old Man's War
Time dilation occurs only when an object is accelerating. If one reached cruising velocity (presumably near the speed of light) no time dilation would occur.
The main advantage for the traveler is actually the length contraction, rather than the time dilation. The distance to the target shrinks with the Lorenz factor.
Right. I was just addressing the misconception (that I had for many years) that time dilation is relative to velocity, but Relativity ties it to acceleration.
Your original conception was correct. Time dilation has nothing to do with acceleration. It is strictly a function of relative velocities (and gravity wells)
Cannot remember the reference, but I believe I read something a long time ago about mass approaching infinity as it approached the speed of light. Hopefully we loose all that weight as we slow down or our destination will overwhelmed with some very chubby people.
Yeah, our mass approaches infinity from the perspective of Earth but not from our own perspective.
Thank you. I was going to mention time dilation, but you've done it far better
Honestly, it’s probably better to set the bar lower and use more primitive but currently feasible fission/fusion based propulsion maxing out at 0.1c and go all in on expanding to every rock in the solar system due to the dramatically shortened travel times. Although if we’re still exploring realm of basically science fiction tech, rather than antimatter, we could spend maybe a century or two just building enough orbital solar farms close to the sun to condense massive amounts of energy into a tiny point to create a minuscule black hole, which could power spacecraft with enormous amounts of energy indefinitely as long as you periodically chucked any sort of normal matter into it to stave off collapse due to evaporation. It’s still phenomenally dangerous, but probably a lot safer than storing antimatter for prolonged periods of time, plus you don’t have to expend tons of energy making new antimatter to refuel, just throw some normal space rocks or collected hydrogen gas into it and allow the black hole to do the mass/energy conversion for you via hawking radiation.
It's important to keep in mind though that you don't actually have to send signals back by signal. If you're making a 28 year trip to Andromeda, you can theoretically make a 28 year trip back with letter or 10,000, thus allowing very slow but real communication between the two locations.
You can make a the 28 year trip to Andromeda and the 28 year trip back, but when you get back, the Earth and everyone on it will be 4 million years older.
Thanks for the correction lol. Forgot that the 28 years was with time dilation.
I screenshotted your comment, I think I’m going to study it.
There is!! It’s Hail Mary by Andy Weir and it’s incredible
Antimatter drive: converts one hundred per cent of its fuel to energy (Penrose). If the drive is shooting particles out of its butt at very close to the speed of light, a microgram might create thrust of a thousand tons. Verdict: possible. But I'm just your everyday Dumas and might be shooting out of my butt...
Space debris: huge problem. One solution might be a very long cylinder of aerogel, a couple of kilometres thick, in front of the spacecraft. Another might be a Star Wars Death Ray blasting incoming matter into plasma. Verdict: possible.
Shielding: huge problem. Sand is only a partial solution for two reasons. One, the mass. Two, incoming matter won't create the normal Hollywood explosion because there's no air, but the sand will explode. The Van Allen Belt is a kind of Faraday Cage. If that can be scaled down to a reasonable size, my verdict is: possible.
Artificial gravity: ridiculously easy. Acceleration and deceleration create gravity, but let's say that the supply of antimatter fuel is finite and for much of the voyage, the spaceship will be coasting and gravity will come from centrifugal force. The inhabitable parts of the wheel-type spaceship won't be a continuous ring. They will be modules like large shipping containers, ten or fifteen metres in cross-section and maybe forty metres long. The wheel has spokes. At the end of each spoke is a fitting like a turnbuckle. A module fits inside the eye of the turnbuckle, and can rotate within that eye. In the changeover from acceleration to free flight, the turnbuckle turns ninety degrees and the module turns ninety degrees within the eye. Result: flat floor, direction of down within the module is consistent.
Dzhanibekov: the spaceship will need some sort of ballasting system, like water being pumped around, to prevent any chosen diameter from becoming a privileged axis. Otherwise, I don't think there's a problem. The number of points on the circumference of a disk is infinity to the power of infinity and there's no reason why any random point and its diametrical opposite should lie on a privileged axis.
Chow: hydroponic farms.
Genetics: a mission of say one hundred colonists may not have sufficient genetic diversity. At present there's a ban on gene correction. That would have to be lifted.
Interstellar travel requires two magic technologies, namely antimatter drives and radiation shielding. Before these become reality we're probably looking at a minimum of fifty years from now.
50 years? First to capture enough energy to create large quantities of antimatter (which I think would have to be space-based), then to create the antimatter, then to store the antimatter, then to create practical propulsion using antimatter, I think 500 years is probably unrealistic. I think closer to 1,000.
For the genetics, if you send 100 colonists, even if you genetically remove any disease, after enough generations you basically have a population of clones, which isn't good. I think for colonization you'd want to take frozen embryos or frozen gametes with you so you bring along the genetic diversity you need for when as the population start growing. I guess if things are sufficiently advanced, another option would be to use genetic engineering once there to introduce artificial genetic diversity to each new generation.
The frozen gametes idea is simply brilliant! I'll write it into my novel. The artificial diversity too. Good thinking Batman.
(In the process of recombination, genes get shuffled around a lot anyway.)
Re the creation of antimatter: "Any sufficiently advanced technology is indistinguishable from magic." ~ Arthur C. Clarke
"Prediction is very difficult, especially about the future." ~ variously attributed to Niels Bohr and Yogi Berra.
You veered into fantasy with “assume antimatter fuel”. Naturally occurring antimatter has long since annihilated itself, and the laws of thermodynamics preclude artificially created antimatter as a fuel source.
Why do you say the laws of thermodynamics preclude artificially created antimatter as a fuel source?
Any process we use to create antimatter will require more energy than we could ever get out of it as fuel.
Yes, creating antimatter fuel will not be 100% efficient, so the process will require more energy input than the ultimate output. That doesn't mean that thermodynamics prevents us from creating it or using it. For the amount of energy needed, we would presumably use the Sun as an energy source.
Yes, but you’re not using the antimatter as an energy source the way coal, oil, uranium, or renewables are used (actual net positive energy to fuel civilization) but rather as a dense form of energy storage for propulsion (like using any of the aforementioned energy sources to charge up an electric car battery or make hydrogen for fuel cells).
How on earth would you know that? You have no idea how to make antimatter from scratch.
At speeds like that the CMB is blue-shifted to such high-energy radiation coming at you head on, there's nothing that can continually propel you at those speeds.
Even if you had perfect mass-to-energy conversion, or a power source behind you, there is just no way it's possible for traveling somewhere humans haven't been before. ~99% the speed of light is about when these problems really start to become prohibitive.
I mentioned that in my post. According to my calculation, at .9999c, which is peak velocity for a 49-day Vega trip (30 lightyears), the CMB becomes a red-hot disk in front of you, but still much lower power than sunlight from Earth, so that doesn't become a problem.
It's definitely a problem at 0.9999999999c, which would be the peak speed for a 28-year trip to Andromeda, which at that point the CMB becomes a stream of x-rays with hundreds of times the power of sunlight from earth. But the interesting possible solution would be trying to use it as a power source.
That's exactly the reason for antimatter, because matter-antimatter annihilations are the only way to turn matter completely into energy. So anything else would require orders of magnitude more fuel mass.
A kugelblitz drive could do the same thing without requiring creating and storing antimatter.
Yeah. Though I'd assume creating and harnessing a black hole would be more challenging than creating and harnessing antimatter.
Generating one, yeah probably, although storing and keeping it fueled up might be a decent amount easier, given that as long as you can just chuck some normal matter like some space dust, or a rock, or even non-vital chunks of the ship into it to keep it pumping out power and avoid it totally evaporating and exploding, while antimatter would need constant magnetic confinement in a total vacuum free of any trace of regular matter to avoid catastrophic detonation.
I think I would have changed the title to:
“Interstellar Space Travel Will Never, Ever Happen the Way You Think It Will.”
My vision of interstellar travel is a gradual expansion of civilization. It is far easier to create living space in O’Neill cylinders than to terraform planets, so I imagine a future where the majority of humans live in cylinders orbiting various bodies rather than on planetary surfaces. As clusters of O’Neill cylinders extend outward to the Kuiper Belt and Oort Cloud, they will approach the equivalents of other star systems. Colonization will then happen in reverse—starting in the outer orbits and moving inward.
For people who have never known anything but an O’Neill cylinder, spending 10–20 years aboard one to travel between destinations wouldn’t seem unreasonable. Once colonies bridge the gap from one star system to the next, interstellar “freeways” could be established. Lasers or other energy sources would beam power to spacecraft, making it possible to reach nearby systems (such as Alpha Centauri) in 14 or 15 years. Not comfortable, but doable—without requiring a generational ship.
Another likely scenario is that space travel will be undertaken primarily by artificially intelligent robots. They could slow their clock time or enter hibernation far more easily than biological humans. In that case, non-human entities may be the ones to experience the interstellar adventures we imagine. If they haven’t eliminated human society, perhaps they’ll beam back stories of their journeys and tell us what it’s like and our posterity will get to experience it vicariously through our robot descendants.
I suspect the machine solution is the most feasible. It requires more sophistication, and more miniaturization, and mass production, and massive redundancy. If you fire a trillion tiny bullets full of highly compressed computation and mechanization—basically artificial DNA—then enough hit your target to start a highly accelerated and pre-programmed artificial evolutionary system. Ten years later, you have a fully functional advanced machine colony. This is simply a variation of Von Neumann's idea.
https://en.wikipedia.org/wiki/Self-replicating_spacecraft#Von_Neumann_probes
One other comment. While worrying about not being able to visit the stars, let’s not lose sight of how amazing it would be to visit the other planets in the solar system. One of my favorite YouTube videos of all time: https://youtu.be/iiPmgW21rwY?si=-0Bfuv9IVKXcPsCg
At what cost does all this happen?
No human being can develop normally, physically or mentally or emotionally in one of those cylinders. As far as doing it with robots? That's little more than an unmanned probe. Why do it? So that some kid eating his corn flakes can marvel at the reports coming back?
Nobody outside a few SF geeks would ever care. Much cheaper for us all if you Sci Fi types would just read a Ray Bradbury book.
Why wouldn't a person be able to develop normally in an O'Neil cyllender? Each one would have rotational gravity on par with Earth and would likely have a habitable area around the same size as NYC (based on O'Neil's original specifications)
as Darwin showed, throughout the ages "normal" has changed, and continues to
Good article, Jason. Another spin on what you're saying is that there's no reason for anyone to do this. No organization can profit off the expense of such a trip, there's not trade that can make up for it, no nation will get glory from it in the time frame any ruler cares about. No pilgrim will find a better life on an alien world when they won't live to set foot themselves on it. The personal impulse to explore the unknown falters when the explorer will never see anything but the confines of their ship.
The thing people should be connecting here is that the reasons to never explore the stars, even via multi-decade probes, are the same as the reasons we're wrecking the earth and treating geopolitics like it's the last turn in a strategy game before the board gets put away.
If we were the kind of society that truly cared about the future of humanity a hundred years from now, we would also be the kind of society that found it much easier to imagine the point of interstellar projects.
It's hard to make people care about a time and place they'll never see. We might have been able to before, but... well, look at the reaction when a billionaire shoots a rocket towards Mars, it's all about how that proves we need to tax them more, etc.
In the case of this billionaire, it's one of a thousand pieces of proof that we do need to. Especially when his reasons for wanting to explore Mars range from the impossibly stupid (colonization) to the entirely self-interested (billionaires running away from the earth they destroyed, so, also colonization).
The Earth is far from destroyed, and neither Musk nor Bezos invented fossil fuels.
But even if they did, them advancing space travel out of their own pocket is a virtue in my estimation, even if it will never live up to the promises of Star Trek.
"out of their own pocket"
Also, you may not think the earth is being destroyed. But they do.
In any case, my point in mentioning it wasn't that tax rates are perfect, but that we aren't a people who will wish to explore space any longer. I think this is some evidence in favor.
Most of the technical and cost issues go away with time as Human civilization because so rich that interstellar travel becomes something that can be done as a lark.
The issue remains the basic physics. It will take multiple lifetimes to go to other star system. This means the concept of *traveling* to the other star becomes meaningless, as I explain here:
https://mikealexander.substack.com/p/what-next-for-space#:~:text=Why%20there%20can,and%20can%E2%80%99t%20go.
Physics does not require multiple lifetimes to go to another star system, or even another galaxy. With constant 1g acceleration, you could go to the nearest star (4.3 ly) in 3.6 years, to Vega (27 ly) in 6.6 years, or to the Andromeda galaxy (2,000,000 ly) in 28 years.
In relativity, physics places no limit on the proper time duration of a trip, only on the observed time from a fixed frame of reference.
https://www.desy.de/user/projects/Physics/Relativity/SR/rocket.html
Constant one-g boosts are the equivalent of Harry Potter’s magic wand. Many have explained this. Perhaps most clearly by Jerry Pournell in “Those Pesky Belters and Their Torchships” - Galaxy, May 1974. In brief, it requires mind-blowing massive long-duration power source and even larger stores of boost mass.
It has been frequently reprinted. Here is the text:
https://archive.org/details/Galaxy_v35n05_1974-05/page/n107/mode/2up
The author did mention that the problem with high speed travel was the risk of collisions destroying your space craft. Are we confident that some form of feasible shielding would prevent this?
That’s a problem. But not just collisions. At high speeds atomic particles and radiation become serious threats. Commonly proposed solutions are a large body of ice or metal in front of the ship. Of course, this extra mass makes acceleration and de-acceleration become more difficult.
I don't think risk of collision would be a serious issue, compared to the others. The only likely collisions in interstellar space would be micron-scale dust and individual atoms, not grains of sand. A grain of sand at .9999c would indeed carry the energy of a small atomic bomb, but would be unlikely to encounter. The likely power absorption from the micron-scale dust in interstellar space would, napkin calculation, I think be around 30 kW per square meter. A reentering Earth orbital spacecraft has to shield for an order of magnitude more than that.
Radiation, deceleration, collisions and genetic diversity seem to me to be the biggest, most obvious impediments after, of course, TIME. we are not going anywhere and that may be the ultimate irony of life in the universe. Just seeing another planet w life, much less intelligent life is absurdly remote. Our own electromagnetic signatures are barely 100 years old - anything remotely sophisticated more like 75. So we have sent a weak, diffused signal as far as the nearest few stars. Let’s say they were detectable at distances that include significant numbers of stars - maybe 1000 light years. Odds are lousy for there to be any intelligent life in that range, but even if, that’s 900 years from now. And intelligent life? If not for a 1-in-a-bazillion asteroid hit at the right time and place, earth is still dominated by reptiles that don’t need fire or metal to continue dominating the planet. We should be researching how to survive another asteroid hit - subterranean, sub-sea, sub glacial societies. Populated by Volunteers who can stay for discreet times. It’s the reality we know.
Well sure, can't speak to what we might do when we get infinite rich.
But absent some magical Unobtanium, trade won't finance interstellar colonization, because there's nothing we could find that would make up for the expense of the round trip. Anything we need from another star we'll have learned to make or do without long before we bring it back!
EROEI
Energy returned on energy invested. No such space travel will occur because the payoff is impossible to define, whereas the cost is, to paraphrase the author, unlimited.
Space travel is a sham.
Anecdote: my father was an aerospace engineer, a propulsion guy. Worked on the Mercury and Saturn projects, met Werner von Braun (probably in Huntsville. He went there often). Jet Propulsion Lab as well. But after the moon landings, all that got shelved. His final projects were all D&D business (death and destruction) for the military. That included the Tomahawk cruise missile. The space travel stuff was not remotely cost effective and when I asked him why we did it, he drew a blank. He knew it and never bemoaned having to move on. He was an engineer and they are practical guys.
Lastly, the seemingly unlimited $ coming out of Washington gives too many people the idea that anything is possible, including space travel. It's called hubris. Once reality hits and the phony money stops, all pretense about our expectations will stop as well. That will include space travel. Won't keep satellites from going up. But we aren't going to Mars.
One of the things people forget now is that during the Apollo program, public opinion was mostly against it. I've read that the timeframe of the Apollo 11 mission itself (a couple of weeks, basically) was the only point where Apollo's favorability rating hit 50%.
A lot of people (enough for politicians to take notice) thought it was neat, but also a huge waste of money that could better be spent elsewhere.
I might add that the intervening half-century, unmanned NASA ships have done all kinds of fantastic things, but manned NASA spaceflight post-Apollo 17 has been indescribably lame: We've spent the last 50+ years repeatedly testing whether humans can survive extended periods in a pressurized container in low Earth orbit. The answer is Yes, but we keep running that same experiment over and over. The scientific community long ago lost interest in manned spaceflight and our orbiting space stations because every conceivable experiment that can realistically be done in low Earth orbit has been done so many times that we already know what the results will be before the craft even launches.
The cost of putting a pound into orbit has dropped dramatically in the last few years because of one thing: reuse. SpaceX expects to get many, many uses of each first stage. The Dragon capsule going to and from the ISS is mostly reusable. There are approaches that could drop the cost even more.
Won't matter. Once the funny money stops, the fight will be on for the remaining loot. Trump and his gang are front-running the inevitable by investing in projects before announcements are made. But at least these are infrastructure investments that will eventually benefit the country.
Unless it is a military related project (and many space projects are either openly or thinly veiled military driven) any space project will have to get in line with all the other lobbying efforts. Good luck with that.
Maybe im missing something here, but we dont have a lot of options do we? The sun will balloon into a red giant and nuke the earth. If we move to pluto or something then we dont have access to solar energy anymore. That means we need to jump ship for another star… or just die.
In several billion years the sun will balloon and swallow the inner solar system, yes. Several billion years. Life on earth, and this is including the period of several billion years where it was just a soup of unicellular life, has existed for less time than the time it will take from now until that happens. It's just not at all a relevant problem.
Im replying to a comment saying “there is no reason to do this”
The essay is titled “…will never ever happen”
But it must and probably will… or we will die. Its probably easy to explain the necessity of a generation ship when you can show your kids a video of your planet fucking exploding.
The human race will be long, long extinct by the time that the Sun even begins to lose fusion pressure. This isn't even doomerism, this is 5 billion years! That is an unfathomable amount of time! Humanity could evolve into something different, could upload themselves into a higher dimension, could prove that everything is a simulation after all, get sterilised by gamma ray, we could wipe ourselves out through some means or another, any number of ways.
There are reasons to want to expand beyond Earth, I personally am of the opinion that if you can explore somewhere, you should, but this just is not in the realm of actually being a relevant one.
What exactly is your prescription? No one is actually trying to do interstellar travel.
However, if it becomes relevant ... we will do it.
I got annoyed by you describing interstellar travel like this:
> "Jump ship for another star... or just die"
due to the sun expanding, because that's just not a thing that will ever be relevant to a human being ever. That's really it.
Why can't trade work? We have mechanisms for enforcing actions over a long time-span, and in hundreds or thousands of years, life extension technology could plausibly assist here too. Communication and enforcement is harder, but we adjust the terms of the deal to suit. I agree there are barriers but they don't seem insurmountable.
It's not impossible, but the benefit have to outweigh the cost for it to be a motivating factor. And the cost is (I can't help it) astronomical. So you won't be hauling produce, obviously, but any other manufactured goods are senseless to haul.
I can imagine the information from the result of planet-sized computation being worthwhile to send.
Yeah nah.
Lord Kelvin famously declared at the end of the nineteenth century that everything was discovered and science had learned everything.
You have followed his example.
There are a lot of things that were once assumed to be impossible that have since become possible. But there are a heck of a lot more things that were once assumed to be impossible that haven't become possible.
Intersteller space travel is already possible. It's not breaking any physics.
I figure the difficulty of achieving interstellar travel of any sort, short of a suicide mission, might exceed even the difficulty of turning this ship we're all on around in time for anyone alive today to ever enjoy justified hope for the future.
Yes, and the New York Times published articles by scientists in the early 20th century saying that rocket flight was impossible - just a decade before it succeeded.
But you are underestimating the orders of magnitude involved, which was the whole point of the article. You might want to give it a careful read and showing where it's wrong, not just a flip dismissal.
Just because Past Kelvin was wrong doesn’t mean Present Kelvin is. One of the fundamental assumptions of science as an enterprise is the existence of a Future Kelvin who is correct. The onus of those who cite Past Kelvin to refute a Present Kelvin is to demonstrate that the Present Kelvin is not in fact the long-prophesied Correct Future Kelvin.
He didn't. Kelvin never made that claim.
He didn't. Kelvin never made that claim.
He didn't. Kelvin never made that claim.
He didn't. Kelvin never made that claim.
I find stargazing such a compelling activity because when you realize we're all already on a spaceship together hurdling through the Milky Way, the sky is a bigger window than anything they have on the Enterprise. You can see a quasar a couple billion light years away with astronomy binoculars. Stars being born, stars exploding, nebulae expanding or coalescing to one day form new stars. One January night my friends and I stayed out for four hours in snow to our shins because a near-Earth asteroid zipped past us so fast, you could see it moving past the background stars in the eyepieces.
Guaranteed, no one who owns a rocket company has looked through a telescope since they were a kid, because when you actually look at the universe, you're compelled to confront your own place in it. You realize being a part of the human society we have down here is pretty much all we have.
We’re all in this together: how about we make the best of that, instead of grinding most of the human race into servitude.
I think you overstate the neccesary power of telescopes, seems overly idealistic. I could imagine Bezos or Musk looking through one, thinking "neat", then forgetting about it immediately, or using the experience as part of a speech.
I agree with everything in the article except being “mad about it.” We’re probably the first generation of humans to be offered a fantasy other than the major religion(s) in our place of birth. As alternatives go, fantasy about interstellar travel that inspires us to learn and explore is light years beyond the beliefs that were thrust on all previous generations of humans.
Ridiculous comment
Don't take offense, but your argument is really an argument from ignorance - ie "we don't know how to do this now, so we will never ever be able to do it." Reminds me of people who said in 1900 that heavier-than-air flight was impossible. These arguments rest in part on the idea that we understand physics so well that there are no gaps where we can squeeze in wormholes etc etc. However, there are strong signs that Einstein's spacetime is not the end of the story (and in any case it is very scale limited in explanatory power.) Dark Energy and Dark Matter present gigantic gaps in our knowledge of physics.
I suggest you look into Donald Hoffman's idea that what we call "reality" is not actual reality but merely a "user interface" to reality that evolution gave us to survive & reproduce so that we wouldn't need infinitely powerful brains to handle it all. He calls it "fitness not truth." (He has a TED talk and some other nice videos, but his book "The Case Against Reality" is fantastic.
Hoffman says that we really don't know how many dimensions of space there are. We perceive 3, but that is a simplification. Also we don't know if time is fundamental or emergent from thermodynamics. This leaves open the possibility that we are measuring interstellar distances wrong - the stars could look really far away to our hominin brains that evolved to keep us alive on earth. This might also explain the Fermi paradox - I call this the "wrong radio" hypothesis - not only are we listening on the wrong frequencies but we are on the wrong equipment entirely.
Another source of inspiration here is Kip Thorne's wonderful "Science of Interstellar."
Never say never!
That said incompleteness of our theories doesn’t imply unconstrained freedom Dark matter and dark energy point to gaps in our understanding but they are already tightly constrained by multiple independent observations Any deeper theory has to reproduce those results; they don’t automatically open the door to spacetime shortcuts or radically shorter distances
Yes, agreed, nothing is automatic here!
Okay here's the problem as I see it, and I'm not talking about a science problem. I'm talking about a literary problem. We used to have this awesome genre of fiction where people jumped in boats and sailed off to mysterious unknown continents to meet people who were basically human but completely different from everyone they knew.
Different in interesting and meaningful ways that taught us about the nature of humanity by amplifying certain characteristics. Land of Giants, Land of Gods, Land of Tiny People, whatever. With sea monsters that personified basic forces of nature that everyone was terrified of.
Then we got better ships, and found out what was actually on those mysterious continents, and the frontiers of magic got pushed a little further away each time, until there was no reasonable place we could expect to find magic on Earth.
I think the last example was Erewhon? Where we had to journey to a hidden continent under the Earth to find magic.
Then we got Jules Verne, who entertained the first concept of a space program. Then we got Edgar Rice Burroughs who took the magical continent framework and moved it to Mars. Then our telescopes got too good and there was no magic on Mars, either.
So we had to push the magic back more and more until it required travel to other solar systems, or all the way to other galaxies.
Star Trek is the classic plot of going to an alien place and meeting people who are almost, but not quite like us, so we can explore what makes humans unique in a hundred different ways, by taking certain traits to their extremes and calling them aliens.
But you can't reach the magic aliens without a magic ship, and when the Fermi Paradox started to make us think the whole universe was just an endless series of dead rocks, we came up with time travel twists and alternate universe nonsense that is really just the same misapplication of physics, used in the service of that same old story, meeting people who are almost, but not quite like us.
Or sometimes they literally are us, speculating how our societies would be different if you changed one tiny detail in the river of history.
The magic space warp drive isn't merely a reflection of technological hubris, it's the most elegant solution we could find to a literary problem, where we needed to speculate about the nature of humanity, in a world where we had no mysteries left.
Glad to see someone found the fiction in science fiction.
Anything is possible
Good laugh!
Your answer to why generation ships are impossible are… social issues? I wonder what the kids in the American colonies felt like when they realized they were on a hostile continent thousands of miles away from where their ancestors grew up? The answer is they didn’t really care, because your baseline satisfaction is relative to where you grow up.
Have you considered life extension? If you’re talking about centuries of travel, given the many millions of years (or billions) we have to figure this problem out, you essentially have to be 100% confident this won’t be figured out in a period of time many thousands of times longer than man has had agriculture. Do you think the people building Gobleki Tepe could seriously have predicted the limits of technological development?
Then you bring up Mars, which basically has none of the objections that you just discussed. To make it clear for you, no one intelligent is seriously proposing going to another star system to settle anywhere in our lifetimes. We haven’t even gone back to the moon yet.
Your objections show a lack of imagination, your reasons for caring show a lack of understanding on how space travel improves life here on earth, and your bitterness shows a lack of spirit.
Kids in the American colonies had fresh air to breathe, soil under their feet, blue sky to look up at- you get the idea- real life stuff. It's what humans need. They can't develop properly without it. It's not optional and can only be tweaked so far before a wide variety of consequences begin to sabotage these space workaround ideas.
I swear, you space and sci fi types remind me of the left/woke/trans communities who think they can disregard basic biology and human nature and needs. And it's all just because they want to believe.
You’re retarded, sorry.
Social issues are important to bring up considering that if it takes 1,000 generations to get somewhere, it only takes one generation, or 0.1% to sabotage the mission, refuse to procreate, try to turn the ship around, etc., etc.
Social issues are a reason to expect that it won't be *easy*, but *really hard* and *never, ever happen* are very far apart.
The future is literally trillions of trillions of years (not a few trillion, but much more than a trillion trillions), and we've gone from 98% of the population living a subsistence lifestyle to landing on the moon and having supercomputers in our pocket in less than a thousand years.
Vaguely gesturing at a problem doesn't make something impossible. The author insists on things like "We all think space is roughly a billion times smaller than it actually is" when the "we" are really just people who aren't especially informed or interested in thinking about these things. As if the most obvious objection "Space is really big!" hasn't been thought of by people who like to discuss and think about this stuff often.
The author is a perfect example of the Dunning-Kruger Effect. They know *just* enough to understand that the sci-fi space-opera stuff isn't realistic, but not enough to understand how the most obvious objections have reasonable responses to them. Now there's room for debate on whether interstellar space travel is possible, but a complete novice on the subject coming in and declaring confidently that it's "never, ever possible" only demonstrates ignorance.
First, you're making great points that I agree with entirely. Colonizing Mars is never going to happen. The core is dead; so, it has no magnetic field. Even if you could start producing atmo the surface would be unlivable due to radation. We can try the moon first, but that's also iffy. When we have mastered all the places on Earth -- as you rightly point out -- that at their worst are nothing compared to Mars or space, then maybe we can talk. Mars is worse than the Earth was after being hit by object that killed the dinosaurs. Proof? We're here, aren't we?
I wouldn't mix up "Star Wars" and "Star Trek", though; one is space fantasy with space wizards, and the other tried to eat its own dog food in the form of the science of the time. I'm totally there with you, though. When Data says, "we're 15 minutes from target." Motherfucker! You ain't 15 minutes from shit! Even with warp 10, there's no way you're going to get to a different solar system in 15 minutes! "Star Trek" leaves the distances vague on purpose. They know. But there ARE theories about about how a warp field could be created and maintained; and some experiments have pointed at these theories being possible. It's nothing that is going to happen in the next 1000 years...if ever. We're the same age, Jason; so, I grew up with the same stuff. And I get it. The kid in me is wondering where those warp drives got to too.
Anyway, if you haven't read Adam Becker's book, "More Everything Forever", I recommend it. He talks about this weird "colonize space for the good of the species" stuff and I find his arguments interesting and compelling. Also, he's got a PhD in astrophysics. I kind of think he's got more cred than these other tech douches.
I'm reminded of that great ad with Avery "Captain Sisko" Brooks standing next to the Golden Gate Bridge yelling "Where are the flying cars? I WAS PROMISED FLYING CARS!!!"
If you want flying cars, watch a rally sometime.
Imagine you were transported into the future for just one day. You might want to check out as much future technology as you could, then on your return to the present you would present all those ideas as your own inventions. I suspect that a visitor from the 1950s would be disappointed by today's world. Very little has fundamentally changed.
A generation ship is physically possible, by recycling air, water, etc and growing food. You aren't even denying that. You just don't like it. And would it be cramped? What about a hollowed out, spinning asteroid - that could be fairly large. As for whether future generations hate it - consider a persecuted religious group that is banned on Earth - they might Love a chance to get away and live the way they want to. I'm not saying this would be for everyone - I'm saying that there are groups that would be ok with a generation ship. (Maybe radical. Maybe religious. But that is likely who would sign up for something like this, and like it.) What do you think? Possible?
Geez... buzz-kill.
Note: If you told a human 200 years ago that we would now be routinely manufacturing things like transistors so small you could line up 20 million of them across your thumbnail and that these things would be found in little devices we all carry that can access almost all human knowledge and process 10 to the power of 20 bits of information per second - they might be forgiven for thinking it fantasy.
I enjoyed this article but nearly nothing is impossible.
Anything is possible😄