[meteorite-list] 1972 Fireball (was "Bolides")

From: sterling_k_webb_at_sbcglobal.net <sterling_k_webb_at_meteoritecentral.com>
Date: Wed Jan 18 01:13:00 2006
Message-ID: <006a01c61bf6$37c88230$b9e5fb44_at_ATARIENGINE>

Hi,

    The best source of information on the 1972 Grand Teton
object is this excellent page:
http://comets.amsmeteors.org/meteors/1972.html

    The object was detected by an Air Force satellite, which
makes altitude dtermination possible: "The object first became
hot enough to be detected by the Air Force satellite at a height
of 76 kilometers over Utah. Its closest distance to Earth was
58 kilometers, which occurred over Montana. As it continued
its passage through the atmosphere it finally cooled below the
satellite detection level at a height of 102 kilometers over Alberta."
    The length of the luminous path was about 1500 kilometers.
    In 1974, an estimate of size and mass was published in
Nature, of 1000 meteric tons and about 4 meters in diameter
(if iron). I know SUV's are heavy, but 1000 tons? I make that
about 40 SUV's, unless they're all Hummers...
    The astronomer Jacchia published an estimate of mass
based on observed luminosity of somewhere between 4000
and 1,000,000 meteric tons, with a diameter of 13 to 80 meters
(if a stone, more likely). Jacchia, by the way, who was a meteor
expert at the Center for Astrophysics in Massachusetts, just
happened to witness the fireball from Jackson Lake Lodge
in the Grand Tetons! You go on a vacation, but your work
just follows you...
    In 1994, Ceplecha re-calculated Jacchia's orbit for the
object and predicted a return in 1997, which did not occur,
however, so it would seem the earlier orbit was correct (or
they were both wrong.)
    The Ultimate Authority, the Wikipedia, says 5 to 15 meters
in diameter but declines to offer a mass estimate...
    Even at the lowest mass estimate (1000 metric tons), the
object would have delivered a Hiroshima-sized punch if it had
been pointed a little differently and impacted. The plane of
its orbit's intersection with the Earth passes right through Los
Angeles, so if its earth encounter had been delayed a few
minutes, we could have had the ultimate Hollywood "special
effect!"


Sterling K. Webb
---------------------------------------------------------------

----- Original Message -----
From: "Frank Prochaska" <fprochaska_at_verizon.net>
To: "'Pete Pete'" <rsvp321_at_hotmail.com>;
<meteorite-list_at_meteoritecentral.com>
Sent: Tuesday, January 17, 2006 11:12 AM
Subject: RE: [meteorite-list] Bolides


> Hello all,
>
> If I recall correctly, this bolide was also caught from above by a
> Defense Department satellite. Unless I'm mixing up my stories, they
> calculated the initial mass of the object, the altitude to which it
> descended before it "bounced" out of the atmosphere, etc. Anyone have any
> of that, or am I thinking of a different event?
>
>
> Frank Prochaska
>
>
>
>
>
>
>
> -----Original Message-----
> From: meteorite-list-bounces_at_meteoritecentral.com
> [mailto:meteorite-list-bounces_at_meteoritecentral.com] On Behalf Of Pete
> Pete
> Sent: Tuesday, January 17, 2006 9:01 AM
> To: meteorite-list_at_meteoritecentral.com
> Subject: [meteorite-list] Bolides
>
> Hi, all,
>
> Speaking of the Grand Teton
>
> http://fireball.meteorite.free.fr/1972_08_11/Video/video_g-t.html
>
> http://fireball.meteorite.free.fr/1972_08_11/Video/video_g-t.html
>
> Assuming it was a stony (since most meteorites are) would anyone care to
> guess at the mass behind the show?
>
> That high up and daylight, it would have to be at least SUV size, wouldn't
> it?
>
> If this is a worthwhile question, how about Peekskill, which so many of us
> witnessed - how large would that have been at the start of it's descent?
>
> I realize there are many variables at play, so of course they would be
> ballpark estimates.
>
> Cheers,
> Pete
>
>
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Received on Wed 18 Jan 2006 01:12:53 AM PST