[meteorite-list] What's the highest meteorite ever found?

From: Ed Majden <epmajden_at_meteoritecentral.com>
Date: Thu Apr 22 09:43:33 2004
Message-ID: <006b01c11198$bd24eee0$34974318_at_cc.shawcable.net>

----- Original Message -----
From: dean bessey <deanbessey_at_hotmail.com>
Subject: Re: [meteorite-list] What's the highest meteorite ever found?


> I have wondered if meteorites are more likely to be found at higher
> altatudes (Everything else being equal which of course it never is) than
at
> lower altitudes. The idea of course is that if you are 3 or 4 kilomiters
up
> (Like many dry and barren places in the atacama for instance) the rock has
3
> or 4 km less of atmosphere to burn - and also eliminating the thickest
> portion of atmosphere. (Which immeadiately leads to a second theory -
which
> is, are you more likely to find smaller meteorites at higher altitudes
that
> are almost burned totally away and would not have made it another 4000
> meters).
> From what I understand there is no real evidence to support this (Dar Al
> Gani is only half a kilometer in altitude I do beleive) but I dont think
> that anybody has actually studied wither or not it is true so there is no
> real evidence one way or the other - and much of the higher deserts such
as
> the gobi and large areas of the atacama hasnt been extensively searched.
The
> siesmically active atacama would likely eliminate many meteorites also so
> that would possibly skew the stats also.
> I wonder how much of the rock burns up in the last 4 km to sea level?
> (Compared to the amount that burns up from space to 4km more to go). Would
> different types of meteorites have different burn ratios? (ie: where best
to
> find those achondrites and Cs). Stats on the number of meteorites found at
> various altatudes might be interesting if somebody was able to compile it.
> Cheers
> DEAN

    Land height has nothing what ever to do with the survivability of a
meteorite. The atmosphere is more or less uniform in density as measured
from sea level not the land mass it is over. The survivability of a
meteoroid is dependent on its initial entry velocity, angle of entry, and
type of meteoroid etc. Stones tend to fracture at higher altitudes than a
solid iron would.
End point velocities, or where ablation stops, are in the range of 3 to 6
km/sec. End point heights, or the point where the meteoroid becomes
invisible range from around 5 km to 64 km. The average height is around 18
km. Pribram had an entry velocity of 18 km/sec with an end point velocity
of ~7 km/sec. It first became visible at a height of 98 km and ceased to be
visible at 13.3 km. The Lost City meteoroid had an entry velocity of 14.2
km/sec with an end point velocity of 3.5 km/sec. It became visible at 86 km
and ceased to be visible at 19.5 km.

Ed Majden - American Meteor Society Spectroscopy Project Coordinator
Received on Fri 20 Jul 2001 11:53:44 PM PDT