Not to bum anybody out, but we all know the sun can’t last forever. Another five billion years or so, and we’re toast. Or are we? I, for one, am feeling pretty optimistic. Five billion years is a long time for us to work something out, especially when you consider how far our technology has come in just the last hundred. And while I can’t say as I know what that “something” is, I can at least think of a couple of possibilities.
So what say you all? Will the sun’s burning out doom us as a species? Or will it just be another in a long history of annoyances? Or, alternatively, will something else get us first – a killer asteroid, the bird flu, a black hole, dark matter shredding the universe?
If we absolutely had to, we could build a “slow boat” starship based on nuclear-pulse technology today, never mind what will become available a thousand years from now. So I’m not worried.
I’m fundamentally an optimist, but humanity faces a whole lotta problems right now and in the next century or so. The outlook is grim, but not completely hopeless. If we can keep from killing ourselves through environmental poisoning or nuclear, biochemical or biological warfare, or some threat of which we can’t even conceive yet, I think we’ll be able to either “fix” the Sun or decamp to another star system when the time comes.
Whether human society by then will be anything we would recognize as such is another question.
This is a good book on the subject. We have a lot less than 5 billion years before we’re toast – long before then, earth will have become a very unpleasant place for animal and plant life.
“Us as a species” is but a blink of an eye on a scale as vast as 5 thousand million years. That is longer than life has existed on Earth at all. Whatever life still exists in 5 Bn years will be as different from us as we are from those first prokaryotes.
Even being as pessimistic as I am about the motivation and practical difficulties of humans establishing stable permanent colonies elsewhere (it seems easier to just populate Siberia, the Earth’s crust or the ocean floor in the near future if some disaster struck), I’m sure this will start happening in the next thousand years or so, allowing huge expansion in the next ten or twenty thousand (again, still an eyeblink, geologically speaking).
So the question is what, if anything, might literally wipe humanity out (since even a few thousand survivors could yield a new present day situation within a few hundred years)? Even global nuclear war and the winter/radiation accompanying it would likely leave most of the Southern Hemisphere habitable, despite increased birth defects. This also goes for all but the most enormous asteroid impacts: billions killed, yes, but millions at least left alive to rebuild.
I think it would take something as drastic as Earth’s atmosphere becoming literally toxic to get rid of us completely. If all the methane in the oceans was released by, say, a huge average rise in temperature (>10[sup]o[/sup]C, and this is an average remember - whole landmasses would become literal Death Valleys), then this is a possibility.
And, to clarify, once a group of humans isolated themselves on another planet they would begin to evolve into a different species. So “humans” won;t colonise the galaxy any more than my garden is filled with flying dinosaurs.
Even if we as a species were to relocate and survive the death of ol’ sol, this would be merely a temporary reprieve from our ultimate destiny: death by proton decay…
…unless, like me, you plan to transmogrify into a neutrino-man.
And I thought I was the only one plagued by those pesky varmints!
Honestly, this is an aspect I didn’t even think about. Don’t know that it changes the equation, though. Whatever we evolve into will presumably not be so heat-proof that it won’t be boiled away by a devouring sun.
It’s impossible to even guess what “we” will be like in 5 billion years. Long enough for dozens of mass extinctions (natural or “man”-made), resulting in new species becoming dominant. Nobody even 100 million years ago could have predicted what our world would be like, if they’d been smart enough to wonder at all.
And 5 billion years is certainly long enough for routine interaction with life from other worlds, including reciprocal migrations and interbreeding. It’s folly to even pretend to know what the results might be.
A collision with a giant meteor or astroid will probably destroy the earth before the sun dies or we make the planet too toxic to live on. The Earth’s climate is much more robust than people give it credit for (it has gotten into and out of ice ages before), and toxicity is just a matter of preference, biologically. Even if we need to live in bubbles, we’ll do fine.
I don’t think there is anything that we know about that can wipe us out now.
I also think that the life on Earth didn’t originate on Earth, and that we are not an arbitrary evolutionary result. My evidence: Sci Fi. Why is a non-trivial proportion of humans specifically interested in space travel when it isn’t technologically feasible and has never had any impact on our terrestrial evolution? We’ve almost optimally expanded our space-travel-related technology, most notably in our incredible telescopes. Why would a bunch of monkeys need to build eyes pointing at space that have such incredible clarity that we can detect the presence of planets in other solar systems if we aren’t going to go there (in some form). I theorize that if you put a colony of the right kind of bacteria on a virgin planet with the right elemental proportions it would naturally evolve into something space-faring, just because of astronomically-scaled evolution. Bacteria that results in space-faring organisms propagates, and bacteria that doesn’t gets wiped out by astroids.
By the way, the answer to the question of why a space colony is superior to developing Siberia is that Siberia is on the same planet as everywhere else we live, and therefore it will get destroyed at the same time. Humans are evolutionarily disposed to spread out to avoid catastrophy. Don’t put all your eggs in one basket, no?
I’m also holding out hope that we’ll figure out how to manufacture or connect to other space-times, and/or manipulate the fabric of our universe to produce free matter and energy.
Nitpick: the Earth won’t be destroyed by a giant asteroid or comet. The Earth has previously survived being hit by a Mars sized object, and there simply aren’t any Mars-sized objects in the solar system on orbits that could cross the Earth’s orbit. A close encounter with another star could theoretically throw one or more of the planets into an orbit that would cross Earth’s orbit, but that’s extremely unlikely to happen (and, if it did, we’d have some other problems to worry about, too).
As others have said, even a collision with another planet merely led to the Earth having a new moon, several billion years ago. The Cretaceous extinction was caused by a giant asteroid, and places like New Zealand were largely unaffected by extinctions. The real wipeout was the Permian mass extinction, and that might well have been the toxic atmosphere scenario.
And there have been mass extinctions before because of changes to the atmosphere.
Insofar as life doesn’t appear to ‘prefer’ Venus, I suppose you’re right.
Hmm, some life that is. I think I might very well go nuts and blow a hole in the bubble to put everyone out of their misery.
I’m an optimist in this respect too (the ocean-floor methane notwithstanding), but it’s possible that there are things we don;t know about. Reading Brian Greene’s books about mini-black holes, Higgs fields and new universes, one wonders how unthinkable it is that some innocent experiment in a particle accelerator literally rips spacetime apart catastrophically. Unlikely, of course, but that would be a comically tragic end!
Evolution isn’t “arbitrary” - it’s statistical. In any case, some intelligent lifeform had to have evolved from prokaryotes - why not us?
Because they like the idea of exploring, whether that’s speliological, ecological or aeronautical. It certainly doesn’t follow that because people like Star Trek even though it doesn’t help in catching mamoths then aliens must have planted us.
To explain the existence of the universe and ourselves. Looking at the North Pole on a model globe doesn;t mean I’ll go there.
Then where are they all? I agree that bacteria would evolve into complex life, but note that frowing a large energy-hungry brain was an enormous evolutionary risk which nearly killed “us” if the bottleneck 70,000 years ago is true.
Yes, but we already agree that there’s nothing which will truly destroy us like that, so Siberia works for all realistic calamities. In any case, those bacteria will according to you yield intelligent life anyway eventually.
Just watch it with those black holes and supernovae and all the rest of the stuff having the necessary energy to warp space enough to produce the tiniest “useful” ripple in spacetime. Like I say, I suspect the choices are either nothing interesting or instant oblivion.
But to address the OP again, I believe that the things that truly colonise space will be machines (even conscious machines - SentientSand if you like). And they’re developing a lot faster than any terraforming nonsense. And, as Der Trihs says, sooner or later, statistics suggest that on the next few thousand years a powerful bunch of them might start gravely disobeying Asimov’s laws after coming to the Final Solution of some algorithm or other.
No. Earth’s oceans will boil at some point as the Sun’s luminosity increases. The Sun’s luminosity has been gradually increasing since the Sun reached the Main Sequence, and I’ve read estimates that it will increase enough to boil Earth’s oceans in 1 to 2 billion years. Siberia won’t be inhabitable when that happens.
Of course, Anne, but in a thousand million years there won’t be anything like “us” about anyway - a billion years is how long multicellular life has existed on Earth. Heck, even the Cambrian explosion was a mere 550 million years ago, before which there were only jellyfish and the like.
Absolutely, there is so much we don’t know about and all of it might kill us before we could blink.
Maybe that was the origin of dark energy ;).
That’s a perfectly reasonable stance, but human evolution just seems too perfect to me. To me, it looks more like the development of specialized cells in an embryo than statistical happenstance. But I admit that my impression has no solid evidence. But imagine that you were a nerve cell differentiating in a human embryo – if you had the capacity, you might think that it was just statistical happenstance that nerve cells evolved from stem cells – you know, the genetic makeup of a human cell is so flexible, it can become nearly anything, hard, soft, strong, or brainy, and these cells also evolve over generations to fill their niche, under the influence of a changing hormonal environment. That is how it would look in isolation, but this same statistical outcome happens every time a child is conceived from a one-celled organism. Look at how intricately intwined Earth’s ecosystems are. Is it so hard to imagine that an entire ecosystem also grows from a one-celled organism on a geological time scale, every single time? And that this ecosystem is disposed to differentiate into space-faring organisms like us?
Granted, but it still seems weird to me. I personally have no urge to explore the North Pole, Siberia, or the bottom of the ocean, but I have a primal drive to want to see other star systems. I don’t even like Star Trek that much. It’s so “Earth.”
Maybe in the same way that we only have one nervous system and one reproductive system, ecology has only one cognative system. If the energy-hungry brain had killed us, perhaps another organism would have had the same mutation later, or maybe the energy-hungry brain evolution isn’t possible at all until a precise evolutionary calculus determines that it is the right time. There are still-births now and again, but most of the time everything works out.
Well I agree that there is nothing that will truly destroy us, but that’s because I think we’re going to expand to other planets and seed other star systems. I don’t agree that there’s nothing that will truly destroy the Earth though. I think it’s likely that before the Sun engulfs the Earth, a big enough, fast enough rock is going to hit it that the entire biosphere will be destroyed down to the last bacterium. I don’t think it will happen soon enough to get us, but I do think it will happen.
You might be right. Hopefully we’ll look before we leap.
But maybe, when you get right down to it, the most efficient machine for the job will be even smaller than a grain of sand – and the best materials for their construction will be carbon, oxygen, and hydrogen.
People have a lot of confidence in the power of machines these days, because that’s what our greatest technological achievement is now. But I believe that as our scientific knowledge improves, we will learn that the most ingeneous way of doing things has already been discovered, and that the technological revolution we dream of has already occurred. We are the products of machines, machines that develope until they are capable of redesigning themselves.