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Re: Listening to Leonids



I wonder where the folks in 1719 got their VLF receivers.
Skip

-----Original Message-----
From: Brian Whatcott [mailto:inet@INTELLISYS.NET]
Sent: Monday, November 26, 2001 6:59 PM
To: PHYS-L@lists.nau.edu
Subject: Listening to Leonids


NASA News is carrying an interesting story [excerpted below] which seeks to
justify the long held story
that people have "heard" meteorites passing many miles overhead,
simultaneous with their apparition.

Sincerely

Brian W

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

<http://science.nasa.gov/headlines/y2001/ast26nov_1.htm?list67990>

November 26, 2001: All at once there was a eye-squinting flash of light and
a strange crackling noise. Puzzled sky watchers looked at one another ...
and confessed: "Yes, I heard it, too."
Hearing meteors? It could happen -- and indeed it did, plenty of times
during this month's Leonid meteor storm.
...
"I am sure I could hear several of the meteors," recalled Karen Newcombe, a
Leonid watcher from San Francisco... "Several times when a Leonid with a
persistent debris train flew directly overhead, I heard a faint fizzing
noise [instantly]." There was no delay between the sight and the sound.

... in 1719 astronomer Edmund Halley collected accounts of a
widely-observed fireball over England. Many witnesses, wrote Halley,
"[heard] it hiss as it went along, as if it had been very near at hand."
Yet his own research proved the meteor was at least "60 English miles"
high. Sound takes about five minutes to travel such a distance, while light
can do it in a fraction of a millisecond. Halley could think of no way for
sky watchers to simultaneously hear and see the meteor.
Baffled, he finally dismissed the reports as "pure fantasy"...
Colin Keay, a physicist at the University of Newcastle in Australia, not
only believes in electrophonic meteors, he's also figured out what causes
them. According to Keay, glowing meteor trails give off not only visible
light, but also very low frequency (VLF) radio signals. Such radio waves,
which oscillate at audio frequencies between a few kHz and 30 kHz, travel
to the ground at the speed of light -- solving the vexing problem of
simultaneity. ...

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Brian Whatcott
Altus OK Eureka!