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 ______________________________________________ Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list