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In lugnet.space, Jason J. Railton writes:
>
> Actually, I seem to remember that the moon's pull on the tides is mutual
> (the moon is affected by the gravity of water on the Earth), and because
> tidal waters drag across the surface (thus slowed by friction), this is
> gradually decelerating the moon's orbit. So, it's orbit is very slowly
> shrinking...
Whoa, that's something I never thought of before! It kind of raises
an interesting idea, too. If this is always a trend for the
satellite (i.e., "moon") of any planet with large amounts of
liquid on the surface, then maybe over time there is a general
tendency for the satellite's orbit to decay. As the satellite comes
closer to the planet the gravitational effects begin to wreck havoc
on life habitats (relatively speaking). That could be yet another
time limit for the survival of life on a planet, aside from stars
going supernova, 3rd-object impacts, etc. The moon(s) increasing
proximity alters (or destroys) the environment such that the lifeforms
become extinct. Or perhaps such that it never gets to form in the
first place, which could be another factor that reduces the theoretical
number of "habitable" planets in a galaxy.
KDJ
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LUGNETer #203, Windsor, Ontario, Canada
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Message has 1 Reply:
Message is in Reply To:
| | Re: Couldn't resist
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| (...) I never spotted this before, but it's further proof that there's negligible friction in space. If there was, the Moon would have slowed down in it's orbit and fallen to Earth, and the Earth would slow down and fall into the sun. Actually, I (...) (23 years ago, 2-Jul-01, to lugnet.space, lugnet.off-topic.geek)
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