Walter branch wrote:
<Traveling over eons to make it to the inner solar system, how can a
meteoroid stream stay intact enough to cause a tiny strewnfield on the
Earth? I would not think that the Earth's gravitational field would be
strong enough to do what Jupiter did.>
The small strewnfields are caused not by meteoroid streams, but by an
asteroid which is gravitationally clumped rocks and not a solid chunk. Because
they are just gravitationally attached to each other the earths gravity
probably starts separating them and then the atmosphere easily separates them
farther.
<Also, I know I have asked this before but I still don't understand how
researchers can determine cosmic ray exposure ages for a meteorite which
ablated a significant portion of the material that absorbed most of the
cosmic rays and which may have fragmented in flight through the Earth's
atmosphere. >
One way of doing this is using Neon isotopes. I forget the exact details,
but the relative abundances of the neon isotopes can be used to determine
depths. This can then be used to make a correction for depth for the other
noble gases which are then used for calculating the CRE.
--
Eric Olson
7682 Firethorn Dr
Fayetteville, NC 28311
http://www.star-bits.com
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