Re: Large animal extinctions: extinction-ex-astra

Thomas R. Holtz, Jr. (
9 Jul 1996 15:36:19 GMT (Timo Niroma) wrote:

> 1. How can you be so sure that the end of ice age did not have an extraterrestrial
> source?

Two points of clarification:
A) The "Ice Age" is NOT OVER! The actual situation was a series of major
and minor flucuations in temperature, and thus glaciation, and thus
sea level, and thus habitat distribution, and thus organism distribution, etc., etc.
The warm interglacials (with hippos living in Britain) are just as much
a part of the "Ice Ages" as are the glacial advances, just as day and
night are part of the same cycle.

B) The standard model, the Milankovitch Cycle hypothesis, is, if not
extraterrestrial, then certainly astronomical. Although there is some
quibbling as to lead-lag times and such, the data for a Milankovitch-driven
glacial-interglacial cycle is very, very strong.

(Another possibility, solar variability, might come back into vogue,
as recent evidence shows that Sun-like stars may change output by as
much as 5% in less than a decade).