[meteorite-list] Extra-solar material?
From: AL Mitterling <almitt_at_meteoritecentral.com>
Date: Sat, 03 May 2008 11:42:06 -0400 Message-ID: <481C87CE.90502_at_kconline.com> Hi Mark and all, As Norbert pointed out, only small microscopic inclusions have been found that probably contain extra solar material. No specimen that we have ever found is uniquely from another solar system. There are a number of reasons for this. First any material would have to travel great distances (light years) to enter our system. After entering our system, Earth would have to be lucky enough to be the target of such material plus material would have to be recovered after the fall. This puts the odds at great disadvantage. Coming from outside of our solar system the material would have a far greater speed than any asteroidal material or planetary material from inside our system, making the chance of survival less likely. Just like meteoroids that catch up to the Earth's orbit more often survive passage than meteoroids that have a head on collision with Earth survive less often due to forces of going through the atmosphere. We do see these high speed extra solar particals coming in at speeds many times the speeds of our systems material. Such extra solar material would have most likely a far greater age. Over 4.6 billion. Such a meteorite would have the age of it's solar system plus the age of it's travel time to our solar system. The farther away the material came from the greater the age if you figure out the great distances between other stars. The farther away the material came from the less likely it would end up in our system as it should encounter other systems on the way here. Each meteorite in our system tends to contain some of the chemical signature from our Sun which makes it identifiable with our system. An extra solar meteorite would contain a different chemical signature based on the abundance of material that comes from that system. Just as no two stars in the sky contain the same exact spectral make up, no two systems would contain the same solar signature making it possible to distinguish such foreign matter to our system. No doubt isotopes would show a much older age and perhaps even unique types of isotopes that would puzzle our scientists. Maybe a fourth or fifth type of oxygen isotope that we use to distinguish Earth/moon system from Vestoids and Martian samples we have. Will have to re-read McSween and find out what he had to say about this and I am sure he did make some comments. Best! --AL Mitterling Mark Crawford wrote: > I'm reading Paul Davies' "The Fifth Miracle". In chapter 6 it refers > to the 1996 discovery by Taylor, Baggaley and Steel of inter-stellar > dust particles entering the earth's atmosphere in the form of fast (> > 70-km/s) meteors: > > http://www.nature.com/nature/journal/v380/n6572/abs/380323a0.html > > It got me wondering as to whether there are any candidates for > meteorites which may be of extra-solar origin. Are there any? How > would they be identified - a suspiciously long CRE age would perhaps > be one indicator? > > Mark > Received on Sat 03 May 2008 11:42:06 AM PDT |
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