The NASA Curiosity rover has found evidence [abstract] of "night-time transient liquid brines in the uppermost 5 cm of the subsurface that then evaporate after sunrise".
The observations point to a daily water cycle supported by perchlorate salts in the soil. Mars should be too cold to support liquid water on its surface, but the briny water has a lower freezing point.
(Score: 1) by SubiculumHammer on Thursday April 16 2015, @01:05AM
The think the question is, "Can life first evolve in a extreme environment?"..which is different than the question, "Can existing life evolve to live in extreme environments?"
(Score: 3, Insightful) by Covalent on Thursday April 16 2015, @01:39AM
This is a terrific question, though I would argue that life almost certainly did originate in a hostile environment (early Earth was no picnic). But your point is still valid. Early Earth may have been more conducive for the formation of life than Mars. But then early Mars was supposedly much nicer than current Mars.
So there are really two possibilities for life on Mars: Early life that originated in a nicer environment and then survived by adapting to the harshness, or life that originated in this harsh environment.
You can't rationally argue somebody out of a position they didn't rationally get into.
(Score: 2) by jcross on Thursday April 16 2015, @02:37AM
There's also the small possibility that life on Mars traveled there from Earth on ejecta from an asteroid impact, or even vice versa.
(Score: 2) by Covalent on Thursday April 16 2015, @03:38PM
Good point!
You can't rationally argue somebody out of a position they didn't rationally get into.