[meteorite-list] Extra-solar material?

[AL Mitterling]

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
>