🚀 go-pugleaf

In article <01bbd664$758bf200$4f6062ce@david-lawler>,
 <dglmal@telis.org> wrote:
>Sedimentary rocks would probably not stand up to millions of years of
>space.

And? There aren't any sedimentary rocks in the existing collection
of meteors, and no spectral evidence of such rocks on asteroids.

>All indications
>> : are that they formed in weightless environments (except for martian and
>> : lunar meteorites of cources). 

>How do small rocks form without gravity?  

Easily. They hit each other and stick. There is no direct evidence of
how asteroids formed, but several moons of the outer planets and
Shoemaker/Levy-9 indicate that some moons and comets are loosely
bound collections of material. So hitting and sticking is quite
reasonable. Gravity only becomes relevant when an object has
grown to a size of ~100 km.

>...The truth is meteors and
>asteroids were apart of something bigger.

The "truth"? Truth based on what evidence? The spectra of asteroids
shows that they were never part of any body larger than about 500 km.
Meteors probably do come from larger bodies: Asteroids. But, with
the exception of the Mars and Moon meteors, there is no evidence
that they were ever part of a body the size of a planet.

> I am not sure how the recent Galileo
> asteroid fly-bys back this up.

Well, the Galileo data does not indicate that Ida or Gaspara were
ever part of a larger body, and the data is consistent with the
theory that asteroids are left over debris from the formation of
the planets. The main anomaly I'm aware of is that the objects
which have impacted their surface have a different size distribution
than what was expected (i.e. more large impacts relative to small
impacts.) Galileo has observed the same thing on Jupiter's moon,
Ganymede. So it isn't a process unique to the asteroid belt, just
one different from impacts in the inner solar system and from
theoretical expectations.

>No body is saying that the earth is a part of a destroyed planet. The
>theory states that the moon is the reminiscence of a destroyed planet this
>also explains why the earth is blessed with such a large satellite.

Two problems. First, the Moon's chemical composition resembles 
the Earth's mantle, not the bulk composition of the Earth or
any other known planet. Second, the Moon's surface has isotope
ratios that exactly match the Earths, in contrast to other planets
and meteors.

                                                      Frank Crary
                                                      CU Boulder