2 ms·

It seems very low likelihood that a life-bearing chunk of Mars arrived and seeded life here. What are the chances that some type of single-cell critter(s) from

It seems very low likelihood that a life-bearing chunk of Mars arrived and seeded life here. What are the chances that some type of single-cell critter(s) from Mars were robust enough to: 1) Survive the trip here with the extreme cold of space, AND 2) Survive the searing heat of entering earth's atmosphere, AND 3) Survive conditions on earth, when they were adapted to the martian environment And that's all premised on a meteor strike on Mars ejecting something with enough velocity to not only escape Martian gravity, but then miraculously happen to score a direct hit on earth (a miniscule angular target to hit). This combination of low probabilities seems to result in an explanation of lower probability than the alternative (life originating on earth) that it's attempting to explain, and of course life originating on an earth-like Mars in same time frame it would have needed to develop here (or maybe also did develop here) doesn't add much more than historical interest.

lagniappe 3y ago
Curious why there is much less interest in the Pleiades, which is made of all of our same material and is very likely a "fork" of earth formed after the original mass that later became earth and moon colliding with another body in early history. https://en.wikipedia.org/wiki/Giant-impact_hypothesis https://en.wikipedia.org/wiki/Giant-impact_hypothesis
- HarHarVeryFunny 3y ago
  Perhaps, but given how sterile the moon appears to be, it's not obvious why the Pleidas would be any different, even assuming they were created by the same potentially life-seeding impact. I can see the purely historical interest in knowing how the earth and moon were formed, where our water came from, where terrestial life originated, etc, but it seems (maybe I'm wrong?) that a large part of the interest in extra-terrestial origin of life consideration is from people who don't want to believe that life is all-but-inevitable in the right conditions and therefore presumably did originate here (and very quickly after earth formed - within a few 100M years). However, if creation of life is an extremely rare event, then the likelihood of it having spread from such a rare source to any other compatible planet seems vanishingly small!

lagniappe 3y ago

Curious why there is much less interest in the Pleiades, which is made of all of our same material and is very likely a "fork" of earth formed after the original mass that later became earth and moon colliding with another body in early history. https://en.wikipedia.org/wiki/Giant-impact_hypothesis https://en.wikipedia.org/wiki/Giant-impact_hypothesis

HarHarVeryFunny 3y ago
Perhaps, but given how sterile the moon appears to be, it's not obvious why the Pleidas would be any different, even assuming they were created by the same potentially life-seeding impact. I can see the purely historical interest in knowing how the earth and moon were formed, where our water came from, where terrestial life originated, etc, but it seems (maybe I'm wrong?) that a large part of the interest in extra-terrestial origin of life consideration is from people who don't want to believe that life is all-but-inevitable in the right conditions and therefore presumably did originate here (and very quickly after earth formed - within a few 100M years). However, if creation of life is an extremely rare event, then the likelihood of it having spread from such a rare source to any other compatible planet seems vanishingly small!