Re: planets

pbrown@polaris.umuc.edu writes:
>Before we all get dissapointed over some programs like these, let's
>keep a few things in mind.  First there is only one planet with life
>of any sort as far as we know.  This particular world _happens_ to
>be small and rocky and _happens_ to have a relatively large moon.
>This is no reason to assume that life _must_ be on a rocky planet with
>a moon.
>
>There is no reason to assume that what this program says happened to
>Earth _must_ happen to other similar planets.  Until they can show
>that _all_ or _most_ life-bearing planets have moons, they're doing no
>more than stabbing at the wind.  It's a neat and curious theory - but
>no more than that.
Actually, they didn't say life *couldn't* have evolved on Earth Mark 1.
They just said the *type we have right now* probably wouldn't have evolved
without the moon. They even said there is evidence there WAS life on Earth
mark 1 at the time the moon is thought to have been formed (in stratified
rocks in greenland)

  They said on Earth mark 1, if it hadn't been hit by another planet,
would probably have some sort of sea animal as the sentient life form.
Also, earth Mark 1 was a mainly watery planet, and very little land would
have stuck up through the seas (at our sea level, earth mark 1 would have
had 3 extra kilometers of water on top of that).

I'm not saying life could *never* evolve on planets with no moons, but the
fact remains, the axis of planets without moons (and they did a computer
similation on this) are unstable and can wobble between 0 and 90 degrees.
They also said that here on earth, a slight 1 degree shift can drastically
alter things (for instance, turning the Sahara from savanna into desert).

However, don't let that get you down. Most everyone who reads about your
worlds won't really think that deep about all the factors. I would have
never thought of the above stuff if I hadn't seen that show. So it really
doesn't matter much in the long run.