by solseed.erid » Thu May 31, 2012 9:57 pm
500pesos wrote:The only way there would be what us humans perceive as 'ice forests' is on a planet where water exists only in solid form (that covers the 'ice' part) but life has developed based on a different chemical substance which on that planet (because of its gravity and temperature) is liquid, off the top of my head, say, ammonia. Theoretically it could be possible. Not on Earth though.
Now, plants - and not any old sort of bacteria and the like - living in vacuum I find this extremely highly improbable to ever develop, for biological reasons, no matter how many gazillions of aeons go by. Were it otherwise, the universe around us would be teaming with vegetation (it obviously ain't).
Also, life existed for (only) 600 million years on Earth you say, which you find it "a blink of an eye in cosmic terms". That may be so, as I cannot say for how long this universe intends to exist in the future. In our planet's existence terms though, Earth will remain in a state where it can sustain life as we know it only for approximately another 600 million years, so, only for another blink of an eye... There's not enough time for anaerobic forests to start on this planet and populate the solar system.
500pesos, I believe you are showing a lack of imagination. We don't see the universe as teaming with vegetation because 1) it is young, 2) we haven't looked very far, 3) vacuum and ice forests are not in the adjacent possible of ocean life.
1) The galaxy is less than three times as old as the Earth. The first generation of stars were without heavy elements so they couldn't spawn life. The second generation were probably heavy element poor and so may not have been able to do any better. Sol is the first generation of stars to be able to support life. Even if the big rip is only 20 billion years away that allows Sol's biosphere about 30 times the time since the Ediacaran explosion to develop before the end. Granted it has to survive the end of Sol but for that it only has to manage to travel to another star in less than 5 billion years which should be easy.
2) Just because ice and vacuum forests are not visible to us doesn't mean they don't exist or won't exist somewhere in the galaxy. As already pointed out, the galaxy is young. It is often pointed out that aliens capable of FTL, if they exist, would be obvious because they would be everywhere by now. It would be tremendous coincidence if they arrived in the vicinity of Earth for the first time in the same century or even million years that we developed the technology to recognize them. But that point doesn't stand up when you are talking about life spreading through the galaxy. Given that the galaxy spins once every quarter billion years, it would be reasonable to assume that vacuum life, once it starts spreading could take a billion years to spread through the galaxy. If the possibility of life is only 5 or 10 billion years old then it would not be a coincidence if vacuum forests spread to our solar system in the same billion years that we developed the technology to detect it.
3) Life developed in the oceans of Earth within a few hundred million years of their formation but took billions of years to colonize intermittently wet land, let alone dry land. It was not in the adjacent possible for ocean life to colonize the high Arctic. But once ocean life colonized wet land, within a few hundred million years it had also colonized deserts and created tundra. Ice forests may or may not yet be in the adjacent possible of naturally evolving life, vacuum forests are definitely not. But given a few more hundred million years even naturally evolving life, may open up a lot of adjacent possible to which it currently does not have access. Add to that, that life now includes humans and artificially enhanced evolution (breeding and genetic engineering) and the next 600 million years (barring something like human-caused destruction of the biosphere) will be a lot longer in terms of evolutionary potential than the last 600 million.
As for the idea that life needs a different chemical basis to survive ice or vacuum. Again you need more imagination. Water can be kept liquid at low temperatures with pressure and dissolved substances; water can be kept warm, even in the vacuum of space with insulation. It may be that life will develop a new chemical basis in order to make the jump, but that basis could be developed by substitution over time. a) Add a small percentage of ammonia or alcohol to the cytoplasm in order to survive a little below zero, b) adapt metabolism to the presence of these substances in the cytoplasm, repeat step a) and b) a few times and you are no longer water based. I am not saying that is how it will go, I am just saying that given a chance, life will find a way.
[quote="500pesos"]The only way there would be what us humans perceive as 'ice forests' is on a planet where water exists only in solid form (that covers the 'ice' part) but life has developed based on a different chemical substance which on that planet (because of its gravity and temperature) is liquid, off the top of my head, say, ammonia. Theoretically it could be possible. Not on Earth though.
Now, plants - and not any old sort of bacteria and the like - living in vacuum I find this extremely highly improbable to ever develop, for biological reasons, no matter how many gazillions of aeons go by. Were it otherwise, the universe around us would be teaming with vegetation (it obviously ain't).
Also, life existed for (only) 600 million years on Earth you say, which you find it "a blink of an eye in cosmic terms". That may be so, as I cannot say for how long this universe intends to exist [i]in the future[/i]. In our planet's existence terms though, Earth will remain in a state where it can sustain life as we know it only for approximately another 600 million years, so, only for another blink of an eye... There's not enough time for anaerobic forests to start on this planet and populate the solar system.[/quote]
500pesos, I believe you are showing a lack of imagination. We don't see the universe as teaming with vegetation because 1) it is young, 2) we haven't looked very far, 3) vacuum and ice forests are not in the adjacent possible of ocean life.
1) The galaxy is less than three times as old as the Earth. The first generation of stars were without heavy elements so they couldn't spawn life. The second generation were probably heavy element poor and so may not have been able to do any better. Sol is the first generation of stars to be able to support life. Even if the big rip is only 20 billion years away that allows Sol's biosphere about 30 times the time since the Ediacaran explosion to develop before the end. Granted it has to survive the end of Sol but for that it only has to manage to travel to another star in less than 5 billion years which should be easy.
2) Just because ice and vacuum forests are not visible to us doesn't mean they don't exist or won't exist somewhere in the galaxy. As already pointed out, the galaxy is young. It is often pointed out that aliens capable of FTL, if they exist, would be obvious because they would be everywhere by now. It would be tremendous coincidence if they arrived in the vicinity of Earth for the first time in the same century or even million years that we developed the technology to recognize them. But that point doesn't stand up when you are talking about life spreading through the galaxy. Given that the galaxy spins once every quarter billion years, it would be reasonable to assume that vacuum life, once it starts spreading could take a billion years to spread through the galaxy. If the possibility of life is only 5 or 10 billion years old then it would not be a coincidence if vacuum forests spread to our solar system in the same billion years that we developed the technology to detect it.
3) Life developed in the oceans of Earth within a few hundred million years of their formation but took billions of years to colonize intermittently wet land, let alone dry land. It was not in the adjacent possible for ocean life to colonize the high Arctic. But once ocean life colonized wet land, within a few hundred million years it had also colonized deserts and created tundra. Ice forests may or may not yet be in the adjacent possible of naturally evolving life, vacuum forests are definitely not. But given a few more hundred million years even naturally evolving life, may open up a lot of adjacent possible to which it currently does not have access. Add to that, that life now includes humans and artificially enhanced evolution (breeding and genetic engineering) and the next 600 million years (barring something like human-caused destruction of the biosphere) will be a lot longer in terms of evolutionary potential than the last 600 million.
As for the idea that life needs a different chemical basis to survive ice or vacuum. Again you need more imagination. Water can be kept liquid at low temperatures with pressure and dissolved substances; water can be kept warm, even in the vacuum of space with insulation. It may be that life will develop a new chemical basis in order to make the jump, but that basis could be developed by substitution over time. a) Add a small percentage of ammonia or alcohol to the cytoplasm in order to survive a little below zero, b) adapt metabolism to the presence of these substances in the cytoplasm, repeat step a) and b) a few times and you are no longer water based. I am not saying that is how it will go, I am just saying that given a chance, life will find a way.