Re:Why extraterrestrial life may not seem alien
by alkonaut on Monday August 02, 2021 @03:29PM
(#28041494)
Of course the environment will determine life forms. What the article says is that if there is a gaseous atmosphere, for example, then selection will reward animals that are able to move through it. That means for organisms that are heavier than the surrounding atmosphere - most likely - wings. For liquid environments, there probably aren’t that many locomotion techniques that are both effective and missing on earth, meaning when we see something swimming in water on a different planet it’ll look like a jellyfish, octopus, fish, worm, clam, bacteria, shrimp, horse… or one of the other hundreds of ways of swimming
[ Parent
| on HN ]
Re:Why extraterrestrial life may not seem alien
by rendall on Monday August 02, 2021 @03:52PM
(#28041776)
Once we move outside Earth-like conditions, we should be decreasingly confident about our speculations, not more confident. What are the chemical and physical conditions of a hydrocarbon lake at 5g, -180C, 1 kilotesla and 100 atmospheres? Can we really be confident that "whale" is the best mechanical solution for moving around there? Can we really be confident that "moving around" would even be the best survival strategy? I think not.
Re:Why extraterrestrial life may not seem alien
by alkonaut on Monday August 02, 2021 @04:11PM
(#28041981)
Indeed earth evolutionary processes require earth like conditions. But here I mentioned swim in water which is a pretty strict constraint on temp vs pressure.
That said even in any other fluid I doubt we’ll ever look at an organism and say “it swims like …<blank>“ because there wasn’t an earth organism that swims anything like it. Of course that means comparing to every method of swimming locomotion on earth which is a staggering diversity from the microscopic up to whales.
Unless other forces are involved (e.g electromagnetism isn’t used for locomotion on earth to my knowledge) and the fluid is incompressible like water, then I’m (armchair) guessing “to swim” doesn’t have that many evolvable solutions, regardless of pressure/temperature and the specific chemistry.