[meteorite-list] Periodicity of Falls?

From: Sam Kimpton <bessel_at_meteoritecentral.com>
Date: Thu Apr 22 09:42:02 2004
Message-ID: <3A6CC532.FE966AE3_at_teleport.com>

Mass extinctions tend to follow a 28 million year periodicity.

Because of this there has been some conjecture regarding two possible
mechanisms for perturbing the orbits of Oort cloud objects in such a way
as to cause a comet shower of the solar system these are:

1. A large hitherto unseen companion star to the Sun-the so called
"Nemisis
     star."

2. An periodic Oscillation of the solar system through the plane of the
galaxy.
     This oscillation is something like a sine wave.

Both are somewhat speculative.

It is also interesting to note that of the mass extinction events in
question there is evidence to link six of them to impact events.

Sam Kimpton
Vernonia Peak Observatory


James O,Roark wrote:

> Hi,
>
> Just wondering, there is a periodicity to the collision of cometary
> debris with the earth and to large, mass extinction causing, impact
> events. Since it is apparent that groups of meteorites come from
> specific parent bodies as a result of impacts on those bodies, could
> there be a periodicity to the falls of those materials as the earth
> encounters each impact's debris stream? Perhaps analysis of the
> cosmic ray exposure ages would give us the age of the particular
> impact event for each group of meteorites and estimations of fall dates
> could lead to predictions of the next achondrite fall for example :-).
>
> Or is the data too scarce.....
>
> Jim
>
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Received on Mon 22 Jan 2001 06:41:39 PM PST