> In a message dated 7/12/01 7:55:21 AM, firstname.lastname@example.org writes:
> > The Moon and Plate Tectonics: Why We Are Alone
> > http://www.spacedaily.com/news/life-01x1.html
> >It discusses the fact that the glancing collision
> >that produced the moon, in removing a significant
> >fraction of the mantle & crust, may have served to enable
> >plate tectonics which in turn enables the CO2 recycling
> >that provides a stable environment for life to evolve.
> >If accurate, this tends to increase the number of
> >water worlds and decreases the locations where life
> >may evolve.
> Yes, but doesn't the article greatly overstate the case?:
> >>It has become clear that our Moon is a rare celestial object
> What about Charon? Double planets don't seem to be *that*
> rare. 1 out of 4, once you discount the suggested observer
But did Charon result from a collision like that that formed our moon?
Or was it simply a captured Kuiper Belt Object.... its really just a
hunk of ice.
Between the four terrestrial planets, only one wound up like ours. So
all we know is that preliminary data say 25% of terrestrial planets wind
up thus. We'll have to wait until the Keck interferometer provides us
with more data from other star systems.
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