Moon is not part of Earth but is the asteroid that hit us.....?

Question

Quote from :

http://science.nasa.gov/headlines/y2001/ast23feb_2.htm

Moon rocks are absolutely unique," says Dr. David McKay, Chief Scientist for Planetary Science and Exploration at NASA's Johnson Space Center (JSC). "They differ from Earth rocks in many respects," he added.

"For example," explains Dr. Marc Norman, , "lunar samples have almost no water trapped in their crystal structure, and common substances such as clay minerals that are ubiquitous on Earth are totally absent in Moon rocks."

Also check out http://curator.jsc.nasa.gov/lunar/index.cfm

If the NASA Statements are true

the MOON ROCKS AND EARTH ROCKS are chemically different, THEN

the MOON itself can't be a 'chunk' of earth knocked into space by an asteroid collision.

It has to be the Asteroid itself, after striking earth, Bounced off the earth, but could not hit Escape Velocity and hung in an orbit about earth in the direction of it's original travel.

Answer 1

Highly impossible because there would be a enormously large crater and were that crater was would be traces of moon rock. These traces of moon rock would be scattered about the earth. The moon would have hit escape volcity because it did escape the earth's atmosphere.

Answer 2

The leading theory is that the Moon was struck by a body the size of Mars and the resulting collision threw the material into space that formed our Moon.  The water so associated with Earth and Earth rocks is believed to be brought to the early  Earth by millions of comets that rained down on the planet eons ago.  That same batch of comet also no doubt hit the Moon as well but it's low gravity and lack of an atmosphere caused the vast majority of it to escape back into space.  NASA hoped to find remnants of that water in the shadowed craters of the Moons north pole where solar radiation may not have effected it the way it did on the majority of the Moons surface.

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Answer 3

First, almost nobody thinks it was a "chunk knocked off" for a couple of decades now.  Current theory is and has been that a rock the size of Mars (a primordial planet some call "Orpheus" slammed into Earth and that some of it and some of Earth was blasted back into space and eventually formed the Moon.

Secondly, it it almost certain that when this impact occurred, the "rock" that was flung into space was molten, possibly even vaporized.  Of COURSE it would form differently and have a composition different than the rest.  The lighter gases and water vapor likely mostly escaped.

Put those things together (with probably other factors I've missed) and this is no great surprise.

Answer 4

Is there a question buried somewhere in all of that? I couldn't find one.

That is a rather old quote, and is not the interpretation now accepted by all lunar scientists, Bill Hartmann's "big splat" theory:

http://www.danamackenzie.com/books.htm

I strongly recommend that you read this book, as it reviews the evidence for the various theories of lunar origins in detail, and is highly readable.