From: Mike Hankey <[email protected]>
Happy Labor Day Everyone,
I've heard some people talk about how sometimes meteors can be big
balls of ice.
How common is this? Specifically what are the chances that the PA
fireball I'm looking for could have been an ice ball? That would
really suck.
From: Richard Kowalski <[email protected]>
Hey Mike,
I'm wondering if it is Louis Frank's "Mini-Comets" that you heard being
discussed?
Rather, I think Mike refers to a common cometary origin meteor (not meteorite).
Most meteors are cometary in origin. So yes, many fireballs are made of volatile
stuff. Don't expect any Leonid meteor, however how bright it is, to produce
meteorites for example. They are too volatile, and too fast for that, and
disintegrate completely.
Taurid meteors, another cometary shower renowned for producing autumn fireballs,
are slower, but still, chances of meteorites of them are slim as it concerns
volatile particles (comet Encke debris).
Fast velocity, high orbit inclinations, are all indications of a cometary
origin. Slow velocity and a radiant on the ecliptic point to a probable
asteroidal origin (there are exceptions though!), and then chances are it could
be a meteorite dropper.
Then, there are the stories of lore about chunks of ice reaching earth surface.
Usually these are either hailstones, or ice from airplane wings. But there are a
few stories that are more intruiging. Peter Jeniskens once got a lady telling
him how during a beachwalk a small black thing dropped out of the sky and
disintegrated in the beach sand in front of her eyes, with a sizzling sound.
- Marco
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Dr Marco (asteroid 183294) Langbroek
Dutch Meteor Society (DMS)
e-mail: [email protected]
http://www.dmsweb.org
http://www.marcolangbroek.nl
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