In article <QkRJrZS00iV404k508 at andrew.cmu.edu> "Howard M. Bomze" <hb10+ at andrew.cmu.edu> writes:
>Even if life did come from outer space that does not help at all in
>trying to answer the question, how did life begin? It just put the
>beginning in a different place.
Sounds reasonable, but I think there actually is a reason to think
about "panspermia" (life from space).
The old counterargument to the apparent improbability of the
Oparin/Haldane "primordial soup" hypothesis was that heck, there were
a few billion years to get things to work.
The molecular and fossil evidence is indicating that life arose soon
after the planet cooled down and stopped getting hammered by
crust-destroying impacts. More and more, the time window is being
squeezed; it's now down to a few hundred million years.
This is no problem, so long as the origin of life is probable, or the
Earth was lucky. But if it turns our that there just has to be a few
billion years for a massively complex life form like the last common
ancestor of Earth life to arise, it might become necessary to explore
the possibility that life arose on another, older world.
Not that the hypothesis is testable, mind you.
- Sean Eddy
- Dept. of Genetics, Washington University School of Medicine
- eddy at genetics.wustl.edu