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From: wmartin@brl-tgr.ARPA
Newsgroups: net.aviation,net.astro
Subject: Something else to watch out for!
Message-ID: <11270@brl-tgr.ARPA>
Date: Tue, 11-Jun-85 15:03:14 EDT
Article-I.D.: brl-tgr.11270
Posted: Tue Jun 11 15:03:14 1985
Date-Received: Thu, 13-Jun-85 23:59:09 EDT
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Organization: USAMC ALMSA
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Xref: watmath net.aviation:1626 net.astro:661

There's a rather good weekly radio program I try to listen to called the
"BBC Science Magazine"; I suppose its a teanscription service from the
BBC, and it is aired on NPR stations here (locally on WSIE, 88.7MHz,
Edwardsville, IL). Anyhow, last week's program had a segment about
a curious phenomenon encountered by a Japan Air Lines pilot on a
trans-Pacific flight. (I didn't record this broadcast, so I can't cite
specific figures, as I'm working from memory.)

Anyway, this JAL flight was cruising at some normal jet-type altitude
(like 30,000 ft or thereabouts) some distance above a rather dense cloud 
layer. Suddenly, directly ahead, the pilot saw the clouds begin to rise up
in an enormous bulge. The cloud bulge grew at fantastic speed, and 
soon reached up and sideways for distances measureable in miles. The pilot
took evasive action, but could not avoid flying through the cloud; he
was convinced that he was flying through the results of an atomic
explosion, so he had the crew go on emergency oxygen, and he landed
at the next available site to have the plane checked and decontaminated
if necessary.

Well, there was no evidence of radioactivity, and no ground-based
phenomenon reported that would explain this occurrence. Normal atmospheric
changes, like the formation of cumulus clouds, cannot occur at the rate
observed. The JAL flight eventually continued on to its destination.

What caused this? Well, the theory is that that airplane had the first 
observed encounter with a meteor. A several-ton meteor, of several meters
diameter, perhaps composed of mostly ice with some stony fragments, could
have hit that cloud layer on its way down through the atmosphere. At
meteoric speeds, hitting a dense cloud layer is almost equivalent to 
hitting the ground. The meteor would have fragmented and probably
vaporized, transfering all its enormous kinetic and thermal energy
to the cloud structure in the form of heat. This would have caused the 
observed huge boiling-up of the clouds and the formation of such an
atmospheric structure.

Well, fascinating if true. Here's something else to look up for!

Regards,
Will Martin

USENET: seismo!brl-bmd!wmartin     or   ARPA/MILNET: wmartin@almsa-1.ARPA