🚀 go-pugleaf

Frank Crary (fcrary@rintintin.Colorado.EDU) wrote:
: 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

--
****************begin r.s. response*******************

	re..
		"...Easily..."
	(posting cited above) ...

	how long would that take?
	if the earth formed
 	that way ...
	why are these not planets too?

****************end r.s. response*********************
Ralph Silverman
z007400b@bcfreenet.seflin.lib.fl.us