[meteorite-list] Observed lunar meteorite impacts hit 100

From: Mark Ford <mark.ford_at_meteoritecentral.com>
Date: Thu, 22 May 2008 10:42:50 +0100
Message-ID: <29A9DB45B84970458190D7D39BD42C492C27F1_at_gamma.ssl.atw>

Good point Larry.

But I can't understand why people are still carefully distinguishing
between comets and Asteroids?, I think by now we can assume they are
basically one and the same, and not some exotic different species. To me
it's just that some rocks are more 'wet and oily' than others...

I'd find it very very hard to believe there are no pieces of comet in
our collections.

Best,
Mark Ford




-----Original Message-----
From: meteorite-list-bounces at meteoritecentral.com
[mailto:meteorite-list-bounces at meteoritecentral.com] On Behalf Of
lebofsky at lpl.arizona.edu
Sent: 22 May 2008 03:09
To: Chris Peterson
Cc: meteorite-list at meteoritecentral.com
Subject: Re: [meteorite-list] Observed lunar meteorite impacts hit 100

Hi Chris:

If I remember correctly (probably an old estimate) about 10% of the NEOs
are thought to have a cometary origin.

Also, many asteroids do contain volatiles (20% or more by weight), just
not as much as your "typical" comet.

Larry

On Wed, May 21, 2008 4:14 pm, Chris Peterson wrote:
> Hi Mark-
>
>
> There have been a few meteorites that some have speculated might be
> related to showers. But most likely, none are.
>
> Nobody even really knows if asteroids and comets are all that
different,
> other than comets containing volatiles. Recently, it has been
suggested
> that a few objects we consider asteroids may in fact be burned out
comets.
> And nobody really knows if the rocky material in comets is
> actually fragile at all.
>
> The best argument against shower-origin meteorites is velocity: most
> shower members are simply traveling too fast to avoid burning up high
in
> the atmosphere. The few showers that have slow components also, for
the
> most part, are low activity- barely above the sporadic background.
>
> The way I'd start a serious investigation of this would be to compare
> fall dates and times with low velocity showers. Where you have a
match, it
> might be worth trying to determine if witness reports of the fireball
> suggest a direction that is at least reasonably consistent with the
shower
> radiant.
>
> Chris
>
>
> *****************************************
> Chris L Peterson
> Cloudbait Observatory
> http://www.cloudbait.com
>
>
>
> ----- Original Message -----
> From: "Mark Crawford" <mark at meteorites.cc>
> To: <meteorite-list at meteoritecentral.com>
> Sent: Wednesday, May 21, 2008 4:29 PM
> Subject: Re: [meteorite-list] Observed lunar meteorite impacts hit 100
>
>
>
>> This got me thinking... some of the lunar impacts are being
attributed
>> to well-known meteor showers.
>>
>> Are there any good candidates for (earthly) meteorites which may be
>> part of such showers, and therefore potentially once part of the
presumed
>> parent body? I guess candidate criteria would be time of year and (at
>> least rough visual) triangulation back to the radiant.
>>
>> Or as many/most showers are associated with comets rather than
>> asteroids, is the material perhaps much more fragile and therefore
less
>> likely to reach the earth's surface?
>>
>> Mark
>>
>
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Received on Thu 22 May 2008 05:42:50 AM PDT