Space bastards vs. space geeks

I told you yesterday that I’d let you know when my copy of A City on Mars arrived. It did! Yesterday! I’ve already started reading it, and I’m already happy with it.

Finally, it’s a book about sending humans to space that takes a realistic position: no jingo, no hyper-optimism, and an awareness that enthusiastic boosterism about space travel is a cult-like religion. It sets up the contrast in the introduction: that there are space geeks who fervently believe in the importance of colonizing space for a variety of reasons (most of them bogus), and there are space bastards who keep crashing the optimism by pointing out the problems. The authors side with the space bastards. So do I.

My opinion is that humans are a kind of animal that is well-adapted to a broad range of climates, but are still dependent on a narrow set of environments — we require plentiful water, about 20% oxygen, trace amounts of carbon dioxide, an air pressure between 100 mm Hg and 800 mm Hg, about 1 g of gravity, etc., etc., etc. We can survive briefly outside that range, but we sure don’t thrive and prosper. If ever you’ve raised tropical fish, for instance, you know that living things are extraordinarily sensitive to minor deviations from their ideal environment, and humans also have restrictions we take for granted. Biologically, we’re unsuited to existence anywhere in the solar system outside our one planet — you know, the one we’re busy trashing, but which will never be as hostile and incompatible with life as any of the other places in space.

We’re never going to build viable colonies elsewhere, even on Mars, which is the next best option outside of Earth, and even at that it’s poisonous and dead. I think I’m more negative about the prospects than the Wienersmiths, but it’s still a relief to find a source that recognizes the realities of life in space. It’s reassuring, even.


  1. remyporter says

    There are no permanent habitats on Antarctica, at least not in the sense that people will be born and die there. There’s permanently staffed outposts there, but that’s not the same as living there. Antarctica is a million times easier to live on that Mars. Similarly, there are no undersea cities, which- it’s worth pointing out- would be pretty resilient to a lot of extinction events that might make surface life unliveable.

    I work in the space industry, writing software for robots, and I have to say: send robots.

  2. Dunc says

    @ #1: Pretty much exactly what I was going to say (apart from the bit about working in the space industry). We’re unsuited to existence on most of our own planet, and all of those environments are vastly more agreeable (and readily accessible) than anywhere off-world.

  3. says

    We need to take a can of Earth biome around with us, because even if we don’t we’ll be constantly leaking it out of our bodies, all over everything. I think it was Bruce Sterling who pointed out that humans’ inevitable companions in the colonies will be cockroaches. We’ll be shedding skin flakes and hair and poop and fungal spores and dog knows what all else – something will have to eat that, and something will have to eat the eaters or at least their poop, etc. It becomes a biosphere all the way down, when you’re designing out what will eat your cockroaches’ poo. I always figured that, until human noses change, every space colony will smell like a collection of gym socks. Or worse.

    Before we think about colonizing space we ought to be able to build a contained environment here that will last for, oh, I don’t know – maybe 1000 years? [By the way, deep time engineering will be an interesting field – how do we make software, or a shaver, or a cooking system, that will function for 1000 years? Or do we figure out how to breed trees in space and make everything out of wood? 3D printers seem like a good idea but will spaceships be able to make their own plastics without petroleum products around? etc.] When Tesla starts making cars that function flawlessly for a couple lifetimes I’ll think that maybe we can start looking at generation ships.

  4. hemidactylus says

    Borrowing heavily from and embellishing Bezos quite a bit, Elon Musk should be the pioneer and go live on Everest for a year, maybe cutting off his internet connectivity to simulate communication loss. He could experience first hand a less harsh environment than he wants humans to endure on Mars. Everest has gravity. Maybe that experience will instill the humility he lacks so far. If he perishes in such a selfless endeavor I see no great loss to the rest of us stuck here on an unsimulated Earth. Either way we get at least a year of respite from his superior brain.

  5. birgerjohansson says

    I am reminded of the late SF author Philip José Farmer who as early är the late sixties/early seventies said, the priority must be to protect the Earth.

    Also – as I keep saying – space is a place for AIs once general artificial intelligence becomes a thing, they will not need oxygen and are far less brittle than organic legacy general intelligence entities.

    -In addition, big lava tube caves deep under the surface can provide better habitats for humans than the rubbish that passes for space stations today and is the first thing most people associate with space . Many seem to be mentally stuck in the Apollo era.

    A limiting factor is the lack of useful minerals on the Moon and Mars.
    Down here, we enjoy plenty of ores created by plate tectonics.
    The poverty of minerals may be as devastating for colonisation plans as the harsh environment.

  6. birgerjohansson says

    In a SF story published under the pseudonym Olof Johannesson the Nobel Laureate Hannes Alfvén speculated that the big minds of the future will keep humans around the way humans keep horses around after horses have been supplanted- it does not cost very much and it provides a social value.
    Starting off from that idea, these future senior partners in sapience would not mind providing habitats on proper Earth-like worlds just as we make sure modern zoos are adapted to the inherent needs of the species.
    There would be little competition for space, as places useful for machines have other environments than those needed by humans.
    A Mind mind (to borrow nomenclature from Iain Banks) would not be bothered by a local shortage of air, but corrosive dampness might be a bigger problem.

    As for metals not available in crustal ores, it is ‘easy’ to collect that from exposed asteroid cores if you don’t mind travelling for months in hard vacuum.
    The big issues will be energy (photovoltaic cells + nuclear?) and the infrastructure needed for self-replication. Set up that, and the local system should be more robust than a system dependent on a biosphere. I realise the result would not be a magnet for human tourists (the anoxic deep-sea vents are hardly attractive to modern life even if the earliest life started there).

  7. René says

    “Space Bastard.” YAY! Yet another epitheton to add to my self-descriptors! Atheist, antitheist, antiroyalist, socialist, anti-landownership, feminist, inclusivist, ‘woke’ … (I’m sure I can cough up some more), and now proud Space Bastard.

  8. Akira MacKenzie says

    @ 8

    I’d love to, but I’m only a poor low-level call center drudge. When I become a wealthy one, I’ll do some travelling.

  9. Akira MacKenzie says

    Besides, I can also witness the meh of Earth’s geography and the disgusting idiocy of humanity from home, thank you.

  10. Artor says

    Considering how tremendously expensive it is for even a tiny capsule of meatbags to claw it’s way out of Earth’s gravity well, I don’t see a Mars base as anything other than a scientific outpost. If there is ever going to be an economy to make space travel worthwhile, it will be run by miners operating in the asteroid belt. There are uncountable trillions of dollars worth of rare metals that require minimal digging, with no need to lift them off-planet. They can be smelted in space using vast amounts of solar power without poisoning our atmosphere the way we do with terrestrial industry. If we can make the shift, we can save the one place we know is fit for human life, and move our messiest, most toxic activities somewhere it can’t hurt our children.

  11. says

    Part of why so many people believe in space colonies etc. is that they think that eventually all sorts of stuff will be developed if we wait long enough. That’s not the case. We’re limited by the physical qualities of the Universe. It doesn’t matter how long you work on a warp drive if physics doesn’t allow the method you’re trying. People also believe that it’s simply a question of throwing enough money at a concept and someone will find a way. But, to paraphrase a current pharma commercial “Physics doesn’t care.”

  12. wzrd1 says

    Obviously, Mars is a lousy option! Equally obviously, the surface of Venus is a good option.
    Just look at how well that mini-submarine did at the Titanic!
    Now, just add a small amount of molten lead heat…
    Then, we can explore the possibility of colonizing the sun itself, just to be equally stupid in all respects.

    And immediately afterwards, go streaking around the exterior of the ISS.

  13. Louis says

    @ Akira, #14,

    Please don’t do that. Is there any help anyone can give? Anyone you can call? (The Samaritans might be a good idea)


  14. birgerjohansson says

    Wzrd1 @ 16
    My whole adult life, I have pondered Venus and possible ways to make it slightly less horrible…

  15. says

    The one bit of optimism to appease the space geeks is suggesting that the problems might be solved if we think in terms of centuries, rather than decades. Unfortunately, the Bezos and Musks are all promising amazing developments by 2030, 2040, 2050. Maybe 2150, 2250, if we don’t poison ourselves to death first.

  16. says

    Akira: there are people who can help. You’re in Milwaukee, right? I get out to Wisconsin now and then, maybe we should organize a group meetup for the Midwesterners here.

  17. Paul K says

    I came to comment on the topic, but PZ @ 20 has taken me elsewhere: Akira, I’ve been there, and want to add my voice in reaching out. You are so clearly very bright, and passionate, and add a lot to this group. I hope the best for you, even if I cannot do much else. I also live in Wisconsin (on the other side of the State), so I get how our current state of affairs makes for feeling awful, and I don’t live in your situation, nor with your dad. I don’t know that I could come to the meetup PZ mentions (I have both monetary and mobility issues), but it sounds like a great idea.

    The thing I came to say originally is in regard to PZ @ 19: Since I was a kid during the Apollo years, I’ve loved the idea of us getting out of our gravity well and around to the rest of the Universe, and I read loads of SF. But as I got older and learned more, I realized it would not be easy and would take far more time and effort than the stuff I read presented. The space geeks lost me, at first cordially. But then Musk and his acolytes and imitators turned me right off to their idiocy of thinking we could rise right out to Mars in their BFRs. Starship, my ass. Millions on Mars in our lifetimes? Beyond ridiculous. And stupid, too. Why?! Another deep-enough gravity well down into a hellscape to live in?

    On the other hand, to say the word ‘never’ also goes too far for me. I think we will get raw materials from asteroids (using lots of robots, and maybe a few humans). I think we will have humans exploring further than the moon. Partially for dumb reasons espoused by stupid billionaires for ego reasons, but for potentially good reasons, too. I think those forays, and not full-blown colonizing with whiz-bang technology that ignores all the bottlenecks and biological limitations, could lead, in several generations or longer, to something more. And that’s not just fine with me; it’s very cool, and makes me happy to think about and imagine.

    The space geeks are wrong, but they might push and pull us along to something realistic and helpful to the earth, not its replacement. I really look forward to reading this book.

  18. says

    But then Musk and his acolytes and imitators turned me right off to their idiocy of thinking we could rise right out to Mars in their BFRs.

    Yeah, #PhonyStark is just a con-man, capitalizing on the most widely-touted futuristic pipedreams he’s heard about. He picked “Mars colonies” because that’s what he’d heard his fanboys talking about the most. And the same is true of his equally-phony promises of “neural implants” from Theralink doing all those cool things he’d heard about from the same crowd of SF geeks.

    I do agree, however, with the possibility of both mining asteroids for raw materials, and then using hollowed-out asteroids as human habitations in space. Just fill them up with air, set them spinning for the right pseudogravity, and bring in seeds and soil for some nice gardens, if not actual food crops. The outer shell of rock should block most harmful cosmic radiation and particles.

  19. Akira MacKenzie says

    Before anyone goes calling the cops for a welfare check (as if), I’m going to be fine. It’s just that discussion is just getting me really really down.

  20. wzrd1 says

    The only problem with asteroids supplying metals is, there aren’t enough asteroids to even mass in at a lunar mass. Metal rich asteroids are a minority, but they are convenient for way stations for supplies.
    One might get enough metals to make a proper cylinder station or wheel station, which could be spun up to give 1 G and be thick enough to block radiation – maybe. But, one would also have to make the damned thing immense to provide a biosphere and we’ve yet to even wrangle that problem properly. Remember Bioshpere 2 and the mighty debacle it was?
    So, obviously we need to try that out in spaaaaace!
    Because starvation in space is cooler than starvation on Earth or something.

  21. Snidely W says

    Well, if a liveable second planet is the goal, then we will need a reasonable Earth 2.0.
    A protective magnetic field, an atmosphere, some free water, etc.
    All we need to do to make that is that we go to the asteroid belt, lob Ceres at Mars, throw in a few water-heavy comets captured in the asteroid belt. Wait a while for the dust to settle, and Bob’s your uncle, Earth 2.0. © Snidely W.

    If you work this idea into a book, and/or movie deal, I’ll gladly settle for 10% of the gross.
    If some else has already come up with this idea, 5% will suffice.

  22. Paul K says

    Wzrd1@ 25: I’m looking forward to what the Psyche mission shows. Psyche is the largest known metal-rich asteroid, and the probe — with the same name — will arrive there in 2029. But there are other, much closer metal-rich asteroids that would be far easier to both reach and to mine. Two are ‘1986 DA and 2016 ED85…[which] could contain more iron, nickel, and cobalt than the current global reserves (i.e., the amount on the planet left to mine easily) of each material. Just a single asteroid could provide the world’s requirements for these materials for decades.’ The quote is from Universe Today, here: . And that’s just two asteroids.

    We need nothing like a lunar mass of metal to meet our needs here on earth, or certainly in the space above our deep gravity well, when used to aid the well-being of all of us down in that deep well. It seems very doable to me, and sensible. But not cheap or easy.

  23. Walter Solomon says

    Marcus Ranum #3

    Before we think about colonizing space we ought to be able to build a contained environment here that will last for, oh, I don’t know – maybe 1000 years?

    Biosphere 2 might make it that long. Just give it some time.

  24. birgerjohansson says

    PZ Myers @ 19
    It is more realistic to think in geological terms (thousands of years).

    The necessary delta-vee at aphelia for ‘scattered’ Kuiper belt objects 》100 AU is less than 100 m/s to send them crashing down on Mars with their volatiles (water and assorted greenhouse gases). The cost is in travel time.
    So the way I see it, this is a GAI game. Human project managers do not hang around that long.
    The same low surface gravity that makes bones de-mineralise during long stays also make really big lava tube caves possible.

    Let’s say you want to build a 200 m centrifugal ring to simulate Earth gravity (a smaller ring would complete a rotation in less than 20 seconds, probably causing dizziness). The Moon and probably Mars will provide many lava tubes that wide.

    Long-term bases are absolutely possible. Self-sustaining colonies not so much, not in the foreseeable future.

  25. says

    Marcus Ranum @3:

    will last for, oh, I don’t know – maybe 1000 years?

    Old-school pre-CNC machine tools would be good for a at least a century, I’d say. And maybe several. They would still need seals and bearings and other wear items of course, plus an overhaul every couple of decades.

    If you want stuff to last, you have to build it to last. And that doesn’t seem to be in vogue.

    For other things I suspect it’s just not possible. The lifespan of plastics and elastomers is more likely measured in decades than in centuries.

  26. Nathaniel Hellerstein says

    Forget about colonizing deep space. Leave that to the robots.
    Instead, let’s colonize deep time. It’s feasible. Earth is already terraformed.

  27. Silentbob says

    [Oops, I just posted this in the wrong thread so I’m posting again, sorry.]

    The consensus is clearly that space colonization is too far-fetched; but I have the exact opposite problem:

    Given that life on Earth has spread into every possible niche, no matter how inhospitable it may at first have been
    Given that hairless apes have travelled from Africa to dominate every continent of Earth except Antarctica (and often hang out there for shits and giggles)
    Given that 1,000 years ago no rational person could have conceived of technology that would allow people to fly in a metal tube weighing tons at 600 mph and 30,000 feet across the Pacific ocean – but today we take if for granted…

    I just can’t bring myself to believe that intelligent life from Earth will never spread elsewhere. If we destroy ourselves, sure, that’s obviously a chilling possibility. But there simply is no physical law preventing life from spreading elsewhere – only technological challenges – and the idea that life on Earth would just choose to never rise to the challenge is so thoroughly contrary to all our experience up to now I can’t believe it.

    So it’s not the “space geeks” who seem to me the most implausible (implausible though many may be), it’s the “space bastards”. You really, honestly believe life will never spread from Earth to elsewhere? Even though it’s entirely possible? Never? Not in a million years? Not in 100 million?

    Sorry, but you “bastards” believe stuff that’s far too outlandish for me (if you’ll pardon the pun).

  28. Louis says

    @Akira, #23,

    Even if I could call your local cops for a welfare check, it is my long and extensive experience with things like this that cops very, very rarely make anything better. I am glad it’s just this topic, and that you’re going to be fine.


  29. rrhain says

    That’s always been my solution to the Fermi Paradox: The universe wants to kill you. Space is incredibly hostile to life. Yeah, life has managed to spread most everywhere on earth, but the planet itself is hospitable to life. There is plenty of water, a nearby sun to provide endless energy but not so much as to ionize you, and the habitat is large enough to support an ecosystem capable of recycling all the various waste products that life generates.

    None of that exists in space. And since it takes so long to get from one star to another, you have to bring that with you. But to bring all that with you will take so much energy and material that you’ll never be able to get it off the planet. And as soon as you get into space, space is immediately going to start doing its damnedest to kill you and it is very good at killing you. And since it’s going to require generations to get from one star to the next, you’ll have to figure out how to have those generations in space and convince them that the continuing mission to seek out new life and new civilizations is worth it. The closest Star Trek: The Next Generation came to dealing with this was how Alexander didn’t want to be the next Klingon in the Federation…and Worf sends him off to live with his parents or off to the Klingon home world or anywhere except staying on the Enterprise. That’s not possible in space. Your chief engineer is going to need to be replaced at some point. What happens when there’s nobody interested in being the next one? Who is going to keep you all alive when there’s nobody who knows how?

    So, as someone mentioned, the best we could hope for is to have some sort of computer go off into space for us. But that computer is going to have space try and kill it, too. We’re quite lucky that the cosmic rays haven’t destroyed the probes we’ve sent. But even then, what would be the point? The distances are so far and the power to send back a signal is so vast that anything sent out is never going to send a message back that could be heard.

    And that doesn’t even get into the psychological problems of space travel. Like it or not, humans are a social species. For all the introverts who think that living the rest of their lives “alone” would be heaven, our psychologies just don’t work that way. We’d go crazy. And crazy people do stupid things that get themselves killed. And if the aliens aren’t social creatures, if they could somehow remain mentally stable over the literal generations it would take to traverse the void, how did they get the wherewithal to build a space program capable of sending people into space in the first place? The reason we’ve made so much progress in science is because we are able to combine our efforts. A species of loners is handicapping itself.

    So where are all the aliens? At home. “You can’t get there from here” has never been truer.

  30. says

    Saying “We’re never going to build viable colonies elsewhere, even on Mars” is just as stupid as predicting moon colonies by 2050. Never? NEVER?! So the story of human technological history where new and unforeseen advances are made at an ever increasing rate is just over now? Everything in the future is stuck being incremental advances of things we understand how to do now? Sure the computer I’m writing this on would be irreproduceable magic a hundred times over 1000 years ago but in 3023 AD we’ll just be stuck with all the apparent hurdles we face now when it comes to space travel and colonization? Just like we will in 30,000 AD and 300,000 AD? Amazing all of the meaningful progress stopped in the 2000’s. I don’t see how anyone can rationally believe this.

  31. says

    Well, “never” is saying a lot, but I think there’s an argument that if we actually did manage to get the technology for making permanent colonies, we might no longer wish to. We’ll have more important things to do than getting stuck on a lifeless rock.

    It’s the same issue as with generation ships: Once you can build a ship that can last long enough to get through interstellar space and where people can live for generations in reasonable comfort, why exactly do you want to land on a planet? You just escaped one gravity well and now you want to risk getting stuck in another one?
    Maybe you send down a research team or set up a mining camp, but you don’t transplant your whole group off your ship unless it’s failing and you have no choice. And that relates to terraforming as well. It is always going to be harder to terraform a planet than it will be to just stay on the ship that got you there.

    And one more random point: In past discussions like this, people have compared space colonization with our history of colonization on Earth, arguing that we have some inherent drive to spread out. I think it’s important to note that the actual driver of exploration on Earth was to look for something to loot. Space, being mostly empty, is not nearly the same thing at all and I wonder if simple curiosity is enough to sustain the massive effort needed to get space travel to be realistic.

  32. StevoR says

    @Akira MacKenzie : Respect. We don’t always agree but I’d miss your comments and reckon you deserve much better than I hear you get and have. Best wishes from me for whatever little that’s worth.

    @3. Marcus Ranum :

    We need to take a can of Earth biome around with us, because even if we don’t we’ll be constantly leaking it out of our bodies, all over everything. I think it was Bruce Sterling who pointed out that humans’ inevitable companions in the colonies will be cockroaches. We’ll be shedding skin flakes and hair and poop and fungal spores and dog knows what all else – something will have to eat that, and something will have to eat the eaters or at least their poop, etc. It becomes a biosphere all the way down, when you’re designing out what will eat your cockroaches’ poo.

    Fungi. Lots and lots of different species of fungi. But, yes, also insects as the base of the food-chain and detrivores and pollinators and even food sources for us themselves.

    @1. remyporter : “I work in the space industry, writing software for robots, and I have to say: send robots.”

    Yes send robots – just like we did on our Moon* and are doing on Mars. Robots – and then also people later like we sent Armstrong, Aldrin, Conrad, Bean, Shepard, Mitchell, Scott, Irwin, Young, Duke, Cernan, etc.. We can and I think will and should do both. Because we learn and progress by doing so in all sorts of ways.

    I’m very much on the space geek side here and proud of it. Just remember in this context that there have always been people saying X can’t be done whether that was flying heavier than air craft, climbing Mt Everest or even travelling on a train going over 25 mph. History has a pretty strong record when comes to looking back at those people and saying they got it very wrong.

    .* Are still doing in fact. Eg. China’s Yutu 2 mission. ( )

  33. says

    Thanks for the reply LykeX, but I feel like your view is also stuck in the myopia of what is valuable in current societies based on our global culture and technology. Who are we to say what is important to people in 30,000 AD? When answering why colonize a planet I could be short-sighted too and just use my 2023 values and say I’d like a much larger living space than the generation ship, a new biosphere and fossil record to explore. But maybe by 30,000 AD we can make pockets of artificial space, scan planets’ crusts at microscopic levels and make copies of planetary ecosystems? Who knows. Or maybe by then ‘society’ is past caring about such things and resources are going towards some mind technology whoswhatsit I couldn’t grasp anymore than a Paleolithic human could understand writing code for internet ads. The same concept can be applied to your random point- if mass ends up being the most important resource, going to other stars is suddenly the most valuable thing to do. And whatever negatives you think applies to that may have been solved in tens of thousands of years.

    Again, I’m just amazed people think all future technology is only that which we can conceive of being plausible in the year 2023 and human values will be those we have now and not changed or varied by technology (genetic, cybernetic, or things we haven’t created yet).

  34. StevoR says

    @ PZ Myers – 8 November 2023 at 11:23 am : “Uh-oh, Artor, the book addresses that dream as well. It doesn’t really work.”

    In the view of the authors of the book. The reality might well be different and those authors might just be wrong. Hopefully. One way to find out..

  35. StevoR says

    @ birgerjohansson – 8 November 2023 at 12:39 pm : “My whole adult life, I have pondered Venus and possible ways to make it slightly less horrible…”

    Remove some of its mass? Give it a spin – a faster rotation rate. Remove its excessively thick atmosphere or at least much of it. Cool it down.

    Hmm. Use a Star Trek transporter type thingy supersized to beam it from its orbit into say the orbit of Mars so it cools off and maybe swap it and Mars and get three habitable planets in our solar system?

    Slam a sufficiently massive object into it to spin it up, blow off its atmosphere and enough of its mass to make it more Mars sized (maybe a smidge bigger) and thus unable to hold as dense an atmosphere. Make sure Earth is well out of the way when thuis happens. Bonus if you can split Venus in twain then you get a double planet with half Earth mass approx each.. Very cool. Or atleats much cooler than current Cytherean atmos..

    Pour a lot of ice cubes onto it really quickly, add some dust to emulate a nuclear winter. Ice need not be water ice and could come from TNO’s & cometary nuclei which has bonus of tholins which are organic rich. Add sunshade and more to keep it that way.

    Of course all these need work and are speculative but, hey, why not think big & imagine?

    FWIW more seriously I recommend Pamela Sargent’s Venus trilogy (with an extra fourth book I’ve now just learnt of..) if you haven’t already. See : (Minor SPOILERS?)

    Written 1980’s & by a feminist author &, okay, some technomagic in it but ..can we really rule out technomagic in the distant future given Clarkes’s Third Law? (Plus his first law too..)

  36. StevoR says

    ^ Haven’t read it yet obvs but the author is great and her previous novels were marvellous & thought-provoking and loved ém..

  37. unclefrogy says

    your points are well taken. I have thought that given the distances between stellar objects and the time it would take why would any alien even be interested in “invading” this planet since generation ships of probably amazing size would be needed and all the elements of the periodic table are available between here and any other there often without the difficulty of a huge gravity well. Warp drives, quantum drives are just literary devices until we have unlimited power resources to use in them
    It is also important to note that when the age of colonization occurred there no were habitable places that did not have well established populations any where on earth. It would be better to call it a conquest rather then any benign colonization

  38. Silentbob says

    This is fascinating. Entirely by accident I came across a nearly decade old post by PZ where he attributes the following view to “Evolutionary Biologists”:

    Any Darwinian evolved intelligent life should, on balance, expand to fill the galaxy.
    Billions of years of Darwinian natural selection will produce life with an innate drive and capacity to expand. Invasive species take over if they can. Of course evolution is quirky, so they’ll be exceptions. But expansion to fill an empty ecosystem should be the default expectation for all Darwinian life.

    And then in PZs own words:

    … a species that does successfully exploit space as an ecosystem is going to have a phenomenally fascinating future history of radiating forms. Think of the first space colonizers as equivalent to the first cells that evolved a metabolism that allowed them to exist outside the coddled, energy-rich environment of a deep-sea vent. It’s only the first step in a long evolutionary process that’s going to produce endless forms most beautiful… and also unexpected variations. It’s silly to expect that the successful, thriving interstellar life forms will be bipeds adapted to life on a planetary surface, living in large metal shells as autonomous agents crewing a spaceship. The real thing would be alien, and probably terrifyingly incomprehensible.

    Much what I said at #32.