"r" == randyj writes:

r "Dennis Taylor" wrote in message
r . ca...
I'm just throwing this out for the sake of argument, but here goes:
[...]
So, given this, what if one of the primary requirements for life,
for a long
enough period to allow evolution of intelligence, is the presence
of a satellite big enough or close enough to maintain a molten core
and ongoing tectonics? That would certainly reduce the probability
of life in the universe, without requiring a mystical explanation.

r Doesn't the moon also keep the earth's axis from wobbling around
r any more than it does, such that if we didn't have the moon, there
r would be way more climate variation than we now have?

I had to track this claim down recently for a proposal. As far as I
can tell, Laskar & Robutel (1993, "The Chaotic Obliquity of the
Planets," Nature, 361, 608) were among the first, if not the first, to
make this claim.

While it is true that the Moon stabilizes the Earth's rotational axis,
I'm not sure that we can draw any grand conclusions from this fact.
Would life have arisen anyway? If life arose at the bottom of the
ocean, near a ocean-floor vent, I have difficulty understanding why
the climate on the surface would have affected what was happening 5 km
below the ocean's surface.

Once it arose, would life have survived had the Moon not existed? I
think we know the answer to this question. There have been serious
suggestions of a "snowball Earth," in which much, if not all, of the
Earth's surface was frozen. Thus, the Moon's effect in stablizing the
climate could not have been that important, at least for single-celled
life.

Would multi-cellular or terrestrial life have arisen without the Moon?
Again, I don't think we can answer this question.

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