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Terresteral Meteorites Was: Asteroid capture AND ring material escape?
Hello List,
There is an interesting idea inspired from the original thread which I
have only seen broached once here on the list. If we subscribe to the
earth origin of tektites, and SNC transport dynamics, it is not too far
a stretch to hypothesize the existence of terrestrial originating
meteorite. I suggest that there is an Earthly SNC equivalent, which
did not achieve escape velocity and eventually returned to earth. While
I don't know that this could happen in today's atmosphere, there may
have been different conditions on earth which could have allowed escape
velocity.
Somewhere, I have seen the math on the SNCs and there are upper and
lower limits of mass which could be achieve escape velocity and then
survive ablation in earth's atmosphere. If there are orbiting earth
rocks whose orbits decay over the eons they will also be in a size
range which we could perhaps calculate.
But if there are... and I believe there are likely to be, how would we
recognize them? Fusion crusts? Cosmic ray tracks? How would we be
able to know a returned earth crustal or mantle rock? What is it's
nature given its sudden acceleration from zero to over 15
kilometers/second? Would a sandstone survive as a sandstone or would it
vitrify? A basalt? A carbonaceous stone-- Lime stone? What would
happen to terrestrial rocks in space for a few eons?
I happened upon a what could be a swarm of stones all crusted most with
thumb prints (regamorphs) and even with a hard but unconsolidated
interior of sand and mica flakes... Well was I too eager to discard
them as meteorwrongs? Did I behold a terrestrial meteorite? Is there a
history of a fall claim which was discounted because the specimen was
identified as an earth rock? Thanks for you attention. I am eager to
hear your thoughts on what an earth meteorite might look like and how
you envision they may have been altered.
Regards,
Elton
Jarmo Korteniemi wrote:
>>Back to the idea of an ejecta ring around Earth. Has anybody ever made
any simulations of such a dust/ejecta ring around Earth? How long would
it last, and how far away would it have been? (Of course, this depends
on the size/velocity/material/etc of the impacting k/t body.)
As far as I remember, the gas giants' rings would "vanish" unless there
was some supply of new material (moons inside/near rings). Therefore, a
ring caused by impact ejecta should have vanished *quite* quickly...<<
Ron Baalke wrote:
SNIP
> >As far as I remember, the gas giants' rings would "vanish" unless there
> >was some supply of new material (moons inside/near rings). Therefore, a
> >ring caused by impact ejecta should have vanished *quite* quickly...
>
> Correct again, the rings need to be replenished in order to survive.
> Jupiter and Saturn have small satellites near their rings, apparently
> keeping the rings supplied with material via meteor impacts. If
> the Earth had a ring, it wouldn't have lasted very long.
>
> >Not counting the Van Allen or other belts caused by the magnetic field,
> >or the human made debris, is there *any* dust/rocks circling Earth? Say
> >at Moon's distance? I was just thinking of "regular" meteorite bombing
> >on the Moon, and since it doesn't take a *big* explosion to eject debris
> >off the gravity well there...
>
> None have been detected.
>
> Ron Baalke
>
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