[meteorite-list] Just Another Question

[AL Mitterling]

Hi Pete,

I don't think it would be possible for an astronaut to throw an object, 
rock or otherwise out of the orbit of the Earth. (lets not talk about 
the Hassablat that got away) Seems like that would be possible but if 
you think about it, both the astronaut and the rock are in orbit around 
the Sun. Even a hard throw towards the Sun would only start the rock 
moving back and forth in roughly the same orbit the Earth is in. You 
might have better luck with trying to reduce it's energy (a retro so to 
speak throw) so it would loose energy and fall into a tighter orbit 
towards the sun. You have to think about the actual speed the Earth is 
traveling around the Sun. Any throw would most likely not be able to 
leave the Earth/Moon orbit. Even if an astronaut was well away from the 
Earth Moon system in order for the astronaut to not drop directly into 
the Sun he would have to have an orbit around the Sun. So even throwing 
objects without major gravity near by would even be difficult. It's why 
objects in the inner solar system have a harder time coming out (gaining 
energy) than objects have loosing energy and going in towards the inner 
planets and Sun.

Jeff Grossman wrote: to be called a meteorite, an object  had to escape 
the dominant gravitational influence of its parent body.  In this case, 
we would say that a terrestrial (Earth) meteorite would be an object 
ejected from earth by natural causes (i.e., by impact), which entered an 
orbit around the sun and later was re-accreted (fell as a meteoroid, 
became a meteor and then meteorite when it survived passage) by and to 
the earth.

Jeff states: Nothing like this has ever been found.  Its distinguishing 
properties might be a fusion crust, evidence for cosmic-ray exposure in 
space, and lithology that is completely exotic for its find location.  
Without an exposure history (or being an observed fall) it would be a 
very tough sell.

Hope that helps. All my best!

--AL Mitterling

Pete Shugar wrote:

> So if an object were to be taken into orbit and given excape velosity 
> from earth's gravitational well such that it was not in orbit around 
> earth, but in orbit around the sun and at a later time reentered 
> earth's gravity well, passed thru the atmosphere and survived to 
> impact the earth, it would not be a meteorite simply because it was 
> not ejected fron terra firma by natural means? Granted that man made 
> debri isn't classed as a meteorite but non man made material 
> shouldn't  be penalized because an astronaught decided to impart 
> excape velosity to a rock,puting it into orbit around the sun.
> I say material surviving to impact from any source (excluding man 
> made) would and should be called a meteorite.
> Pete