[meteorite-list] Did Earth Seed Life Elsewhere in the Solar System?

[Mike Fowler]

> If, in the Gladman simulation, 30 Earth rocks get to Titan in
> 5 million simulated years, that's 6 Earth rocks per million years.
> Over the life of the solar system, that's 27,000 microbe bearing
> Earth rocks for the Titan environment. Makes it sound like a
> favored holiday destination of Earthly microbes...

Not so many years ago scientists told us that it was impossible for  
meteorites to deliver rocks from Mars to Earth, because they would be  
shock melted by the forces necessary to give them escape velocity.

Now they seem to be falling over themselves with calculations that  
show Earth rocks pelting other bodies like crazy!
I think it shows a little bit of wishful thinking, and also how fads  
can influence scientific research.

Personally, I think they are vastly underestimating the difficulty   
of blasting coherent rocks thru Earth's atmosphere.
More likely, when the forces are great enough to do it tektites are  
the result!  In other words rocks are vaporized.

A low angle impact has been cited as the easiest way to eject rocks  
from Mars, but this won't work on earth because of the atmosphere.   
Could a rock be entrained in the blast column so it could be ejected  
thru the vacuum column left by the asteroid's decent without being  
vaporized?  Probably not, as the ones in the center of the blast  
would be vaporized, and ones at the edge of the column would be held  
back by contact with the earth's atmosphere.

Is any of this testable?  If rocks can be ejected from Earth, then  
there must be millions, to billions accumulated on the Moon's airless  
surface.  Wouldn't some of them be incorporated in the Lunar regolith  
and then returned to Earth with the Apollo samples or meteorites we  
have found?  If the sample size to date is too small, then we will  
have to wait for a permanent moon base.

Sincerely,

Mike Fowler
Chicago