In article 6f7gf.1658$8o6.827@trndny03, Nog wrote:
If comets are made from mostly water-ice, some dirt and organic matter they
had to come from a former water planet that blew up somewhere in the
universe.

Not necessarily. In the dust cloud around a forming star,
there would be lots of water molecules, ammonia molecules,
"dirt" molecules, and a fair number of organic molecules.
Cold temperatures would cause things to be mostly in the
form of ice, but even then, there would be enough energy
for higher organic molecules than methane and benzene to
form, given enough time.

The planet apparently had water and life before it's demise. This seems to
be the natural way the universe seeds it's livable planets and spreads it's
life. There must be lots of Ort clouds and Keifer belts in other solar
systems and other galaxies.

As I said before, this does not have to come from the
decomposition of a planet. There probably are a lot of
Oort clouds and Kuiper belts, especially about stars
which are not part of a multiple system.

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Herman Rubin, Department of Statistics, Purdue University
Phone: (765)494-6054 FAX: (765)494-0558