I think a good amount of Earth had to have been tossed into space just from Meteor Crater impact (forgetting that many other much larger impacts have taken place)
It seems very possible to me that such material could make its way back to Earth in time, or even shortly after impact if the escape velocity was not strong enough to completely break free from Earths gravity. Greg C. --- On Thu, 1/14/10, Murray Paulson <[email protected]> wrote: > From: Murray Paulson <[email protected]> > Subject: Re: [meteorite-list] Scientists Publish 1st Ever Evidence of > Asteroids with Earth-like Crust > To: "Greg Catterton" <[email protected]> > Cc: [email protected] > Date: Thursday, January 14, 2010, 12:05 PM > HI: > > It is interesting to speculate that the Earth may be > hit by meteorites that have orriginated from earth. In the > relatively "recent" past, the earth has been > struck by large enough bodies that could hurl material off > into orbits around the sun. 65 million years is within > reason as a "recent" episode. I believe that some > of the Martian meteorites have cosmic ray exposures of 20 > million years or more. > > > So, How much would a Meteorite from earth be > worth??? > > Murray Paulson > > > On Wed, Jan 13, 2010 at 10:51 PM, > Greg Catterton <[email protected]> > wrote: > > Not > sure if I missed this on here, very nice read! > > http://www.newsdesk.umd.edu/scitech/release.cfm?ArticleID=1812 > > > part of the story: > > "Scientists Publish 1st Ever Evidence of Asteroids > with Earth-like Crust. > COLLEGE PARK, Md. - Two rare meteorites found in Antarctica > two years ago are from a previously unknown, ancient > asteroid with an outer layer or crust similar in composition > to the crust of Earth's continents, reports a research > team primarily composed of geochemists from the University > of Maryland. > > > Published in the January 8 issue of the journal Nature, > this is the first ever finding of material from an asteroid > with a crust like Earth's. The discovery also represents > the oldest example of rock with this composition ever > found. > > > These meteorites point "to previously unrecognized > diversity" of materials formed early in the history of > the Solar System, write authors James Day, Richard Ash, > Jeremy Bellucci, William McDonough and Richard Walker of the > University of Maryland; Yang Liu and Lawrence Taylor of the > University of Tennessee and Douglas Rumble III of the > Carnegie Institution for Science. > > > "What is most unusual about these rocks is that they > have compositions similar to Earth's andesite > continental crust -- what the rock beneath our feet is made > of," said first author Day, who is a research scientist > in Maryland's department of geology. "No meteorites > like this have ever been seen before." > > > Day explained that his team focused their investigations on > how such different Solar System bodies could have crusts > with such similar compositions. "We show that this > occurred because of limited melting of the asteroid, and > thus illustrate that the formation of andesite crust has > occurred in our solar system by processes other than plate > tectonics, which is the generally accepted process that > created the crust of Earth." > > > > > > ______________________________________________ > Visit the Archives at > http://www.meteoritecentral.com/mailing-list-archives.html > > Meteorite-list mailing list > [email protected] > http://six.pairlist.net/mailman/listinfo/meteorite-list > > > > ______________________________________________ Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html Meteorite-list mailing list [email protected] http://six.pairlist.net/mailman/listinfo/meteorite-list
