Hi Doug, all -
Thanks for the great information, Doug.
3He?
Given Raup and Sepowski's map of chaotically periodic extinctions at roughly 26
million year periods, and Morrison and Weiler's fierce opposition to Clube and
Napier's coherent catastrophism, and the resulting lack of research funding,
I'd take Kyte's observation of "the apparent lack of 3He" with scepticism,
noting especially the "apparent" - money may just not have been provided to
look for a 3He marker.
Also, while 3He has been taken for a cometary marker, I wonder about its
abundance in other carbonaceous chondrites. I seem to recall that 3He is a
solar product, so I wonder about its abundance out in the Oort cloud, and in
long peroid versus short period comets. Perhaps Bernd may be able to throw some
light on this.
I also wonder whether in an impact of that size any 3He, along with a fair part
of the Earth's atmosphere, may simply have blown back out the explosive column.
I am sceptical as to Botke's assertion of other much earlier Baptistina
fragment impacts with the Moon, and wonder if those impacts may just have been
other impacts by other comets.
If the injection mechanism is not gravitational effects due to our solar system
passing through the plane of our galaxy as Clube and Napier hypothesize, then
NASA has wasted 10's of millions of dollars looking for "Nemesis" in the wrong
place, and should have been looking someplace that would provide that 26
million year periodicity. (Nemesis being Muller's hypothetical nearby body.)
In any case, for the last 13,000 years the impact hazard appears to have been
from comet fragments. Neither Brenham nor Campo de Cielo have been show to be
hammers, have they? (By the way, doesn't Nantan belong on the hammer list?)
The most recent massively fatal asteroidal impacts I can recall this morning
were Alaska (roughly 32,000 BCE) and Siberia (roughly 25,000 BCE).
To my knowledge, money has not been provided to determine what formed other
large craters over the last six million years. In other words, we don't know
what's hitting us.
In closing this note, NASA's detection budget next year is around $3.5 million
dollars: in my opinion, Weiler and Morrison need to be "relieved".
PS - Smit will undoubtedly shoot down Keller's latest soon, but its not likely
the press will pick it up.
E.P. Grondine
Man and Impact in the Americas
(and where is a nice small impact over an unpopulated area when you really
could use one?
______________________________________________
http://www.meteoritecentral.com
Meteorite-list mailing list
[email protected]
http://six.pairlist.net/mailman/listinfo/meteorite-list
