Hi Larry
I believe the evidence is telling us that oxygen availability has been the limiting factor on the advance of complex life. If oxygen rose early then metazoans might've lept forward - oxygen stress might've even been a factor in their origin. It seems to have been so for eukaryotes, and then in the PreCambrian after the Iceball Earth episodes. If so here, and extant life on the solar planets is related, then even more so on Venus.
My personal thought is that Venus, Earth, Mars and Titan shared a common biosphere in their earliest days - then the planets diverged. Titan froze, Mars lost atmosphere and froze, and Venus ultimately dried up. No evidence yet for such early life - Titan was clement for a mere 0.1 gigayears, then its ocean began its long freezing over, and Mars was wet for maybe 0.5 gigayears - but it's a possibility if interstellar panspermia is correct and we were all seeded from elsewhere.
Adam
Space/Science » in reply to re: Early start
My point is...
The whole thread (34 posts)
- There is a place in the solar system away from Earth (not artificial) where conditions are much more similar to our world than what we find on Mars....Where is it? (n/t)