[meteorite-list] Related Meteorite Falls 11 years apart? Both Hammers! Both L6 Olivine-hypersthene

From: Rob Matson <mojave_meteorites_at_meteoritecentral.com>
Date: Sun, 7 Mar 2010 23:26:02 -0800
Message-ID: <GOEDJOCBMMEHLEFDHGMMCEKNEBAA.mojave_meteorites_at_cox.net>

Hi Eric,

> To answer your question:

> "...Let me counter your theory with one question: Why should a
> meteorite stream have orbital characteristics that are synchronous
> with earth's day, or more specifically earth's geography?..."

> It shouldn't and it doesn't have to have anything in common other
> than be in the same place at the same time.

I guess my point is that if you're going to choose any two meteorite
falls to be from the same parent body, you wouldn't pick Wethersfield.
The odds are already astronomical against recovering two falls from
the same precursor body; placing an additional constraint that those
two falls have to be in the same country (let alone the same town)
removes any chance of it happening in our lifetime.

> There are countless variables to consider, it's not impossible...

Yes, not mathematically impossible. But so improbable that it's
really not worth considering.

> The second piece could have had an 11 year elliptical orbit which
> placed it in that exact spot 11 years later... ;)

Since the two falls occurred 11 years 7 months apart, the only way
they could be from the same coherent meteoroid stream would be if
the stream's orbit happened to cross earth's at two locations. This
is not unprecented (Halley's Comet is responsible for both the Eta
Aquariids in May and the Orionids in October), but it's more likely
for a stream to cross earth's orbit at only one point. In such a
single nodal crossing case, paired falls from a coherent stream
would have to be at the same time of year.

Note that there is no requirement for the orbital period to be
11.58 years. It could be 5.79 years, or 3.86 years, or shorter.
11.58 years divided by the stream's period just has to be a whole
number. And if the stream is large enough and old enough to be
dispersed all along its orbit, then the orbital period can be
anything. --Rob
Received on Mon 08 Mar 2010 02:26:02 AM PST