Impact Scenarios?

[Rich Travsky <RTRAVSKY@UWYO.EDU>]

A recent Science News contained a short article on one Herbert R. Shaw
who says asteroid and comets strikes on earth are not random and follow
a pattern.

He cites such factors as the uneven distribution of mass within the earth 
can influence impacts and consequently hit the same spots on Earth. He 
points to craters from the time frame 50-100 million years ago and
how they form a pattern (Chicxulub crater, Manson crater in Iowa, Avak 
in Alaska and three in Russia).

I also recently read (I _think_ it was an Aviation Week - wished I'd
photocopied the article) about asteroids with companion satelites.
These companions are either small chunks orbiting the larger piece 
and are broken off bits of the larger one or are gravitationally 
captured. At any rate, if one impacts, the other does too, and some
crater sites (moon, etc.) can be explained as the result of a strike
by such a pair.

Interesting, but I'm no geo-physicist. What I am curious about is 
references to other impact scenarios. A reference to a paper or book
for a little background filler?

+---------+    Rich Travsky   RTRAVSKY @ UWYO . EDU
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