[meteorite-list] LEONID'S MORE HOPE FOR COLLECTORS

From: mark ford <markf_at_meteoritecentral.com>
Date: Fri, 17 Nov 2006 09:18:53 -0000
Message-ID: <6CE3EEEFE92F4B4085B0E086B2941B316581CB_at_s-southern01.s-southern.com>

Hi Rob,

The key detail is that particles are essentially sorted according to
their mass in to 'streams' - anything too big would presumably follow a
different orbit to the smaller stuff. Hence most meteor shower
particles are of a similar size (within reason). I think the sporadics
are basically the bigger stuff all jumbled up...


Mark



-----Original Message-----
From: meteorite-list-bounces at meteoritecentral.com
[mailto:meteorite-list-bounces at meteoritecentral.com] On Behalf Of Rob
McCafferty
Sent: 16 November 2006 22:50
To: Impactika at aol.com; meteorite-list at meteoritecentral.com
Subject: Re: [meteorite-list] LEONID'S MORE HOPE FOR COLLECTORS

This is going to be one of my more thoughtful and
intellectual contributions with a serious question

--- Impactika at aol.com wrote:

> Sorry to disappoint you but meteor shower do not
> produce meteorites.
> They are minute fragments and burn completely in the
> atmosphere.
>
> Too bad the Media does not know that.
>


Hmm. While most people with a background including
astrophysics know this - of which I like to include
myself as one - I have often wondered about the old
meteorite/meteor shower conundrum

I am pretty sure there are no meteorites which
correspond date-wise to meteor showers but is this
actually the case?

While the average comet detritus is dust, it is not
impossible, surely, for a much larger chunk to get
ejected from a comet? The current theories of
explosive outgassing would surely allow a chunk that
broke off to achieve escape velocity. Is it beyond the
realms of possibility that one of these may sit in the
orbit of a comet waiting its transition into the
atmosphere?
I will confess, I have not the mathematical skill
(primarily) nor time (secondarily) to work out the
orbital dynamics of a big-enough chunk that broke off.
I suspect that a large chunk is more likely to follow
the orbital path of the main body than the dust which
can get disperesed by radiation pressure quite
quickly, though theres the radiative effect during
rotation which effects orbits too (I forget its name).
Will that cause it to move out of the comet's orbital
path?

We know comets fragment. We have photographic evidence
of it. We know the fragments spread out (ditto). Why
can we not have meteorites from comets?

Just because we haven't yet, doesn't mean it is
impossible. Mass extinctions have not been observed
dur to major impact events yet, either. We all know
that doesn't mean it can't happen or hasn't happened
in the past. I am not sure my scenario is any
different.

That probe which crashed into the comet recently
(again, I forget the name..I have a full time job to
hold down), did it determine the consistency of the
surface?

Are comets and their fragments too fragile to survive
the transition to Earth from space? If they are, then
isn't it time we stopped likening Murchison to a
comet?

NOT SCIENTIFIC BIT.

Or is it that "we just don't know?" That phrase which
is likely to cause me to create "the dead Scientists
Society". A secret forum where top scientists can, in
confidence, air their misgivings and failures in
understanding which society will not let them admit.

Funny, isn't it? As society dumbs down, it expects
the egg-heads to know and solve more! Lazy bast**ds!

Rob McC


 
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Received on Fri 17 Nov 2006 04:18:53 AM PST