In the "closer than you think" vein (per recent discussions with a seismologist colleague):
Tunguska Event, flattened forest in western Siberia, early 1900's, probably a small comet or asteroid;
Amazon Event, widespread fires in Amazon Basin, 1930's, reported by missionaries, probably a large meteorite or small asteroid;
N. Pacific Event, air blast & cloud formation in upper atmosphere, 1980's, observed by airline pilots, probably a meteorite;
Western Australia event, detected by seismic network, early 1990's, probably a large meteorite (searched for but not found);
Greenland event, detected by seismic network and observed, late 1990's, large (?) meteorite fall.
Seems a little reminiscent of Steve Martin as "The Jerk", with assassin's bullets hitting all around, and him not noticing or figuring too much of it.
Gary
Robert
It's true that some of the particles coming to Earth are extrasolar, but that's because, after they are sputtered by their star to a small size, they are blown out of that star system, and some of it goes here. Zodiacal dust falls inward due to the Poynting-Robertson effect (I haven't studied the physics, but you can search on this title), then, after the Sun sputters it silly, it leaves our solar system. I may have underestimated the lifetime, I think it is calculated at about 40,000 years. This is the time to fall, sputter, and split.
Chris
Zodiacal dust has a life on the order of 20,000 years, so why is there any? It's because it is formed continuously by collisions in the asteroid belt. I assume that means there are lots of collisions and therefore lots of asteroids.
This seems a little unclear (with respect to dust lifetime). Across my desk (source unknown) there was a document this morning regarding the complete "decoding" of a speck of space dust -- included in its contents were several red giants and probably a couple of supernova. So I question the dust "life-time" and source figures (though I do not dispute that much of the dust may be produced via the mechanism described so we may be dealing with "distribution" abundances). == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/
== You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/
