[meteorite-list] Report increases and debris streams

From: E.P. Grondine <epgrondine_at_meteoritecentral.com>
Date: Wed, 18 Feb 2009 01:31:50 -0800 (PST)
Message-ID: <758813.76503.qm_at_web36902.mail.mud.yahoo.com>

Hi Sterling -

When you say "Belt" and "Zone", which ones are you referring to?

While since my stroke orbital mechanics is not my strong suite,
It seems to me that you're thinking of an asteroidal debris stream
as being like a cometary debris stream, which is to say rather uniform along its path. I don't think that would be the case. Second, wouldn't the orbit of a asteroidal debris stream would be different than a cometary debris stream; always co-directional with Earth's orbit around the Sun?

E.P.

--- On Mon, 2/16/09, Sterling K. Webb <sterling_k_webb at sbcglobal.net> wrote:

> From: Sterling K. Webb <sterling_k_webb at sbcglobal.net>
> Subject: Re: [meteorite-list] Report increases and debris streams
> To: epgrondine at yahoo.com, meteorite-list at meteoritecentral.com
> Date: Monday, February 16, 2009, 6:00 PM
> Hi, EP, List,
>
> > I don't know if the intersections of the Earth
> > with either cometary or asteroidal debris streams
> > would necessarily be annual.
>
> For an object to intersect the Earth, it has to intersect
> the Earth's orbit at a given point. Points along the
> Earth's
> orbit are dates of the year in the human calendar, so,
> yes, these intersections would be annual (or twice annual
> if the object orbit was similar in size to the Earth's
> orbit
> but tilted with respect to it, a rare chance).
>
> Not only does the Earth have to be at that point in its
> own orbit (a date) but there has to be an object in the
> "stream" orbit that goes through that
> intersection at
> the very same time as the Earth. (This is why there is
> little need to post traffic cops there...)
>
> The orbits of small bodies, however, change rather
> rapidly under the gravitational influence of the larger
> bodies. Such a "stream" would like precess, which
> would move the intersection along the Earth's orbit,
> from one date of intersection to the next or previous
> day, in a time-scale of a few centuries or less. The
> intersection date might change a day every decade
> or more... or less.
>
> This rapid change is why we've never been able to
> pin down a suspected "stream-crossing" from old
> historical observations. Every meteorite whose orbit
> was determined turned out to be from the Belt or the
> Zone... out there, anyway. I found very interesting the
> recent posting that Buzzard Coulee may not turn out
> to be from out there but from an inner system orbit.
> That orbit would be worth checking for evidence
> of a "stream"!
>
>
> Sterling K. Webb
> --------------------------------------------------------------------
> ----- Original Message -----
> From: "E.P. Grondine"
> <epgrondine at yahoo.com>
> To: <meteorite-list at meteoritecentral.com>
> Sent: Monday, February 16, 2009 4:54 PM
> Subject: [meteorite-list] Report increases and debris
> streams
>
>
> Hi Elton, all -
>
> Elton - "Back to a general note: we are seeing weekly
> and monthly spaced
> major fireballs including large meteorite falls."
>
> Perhaps this is just the effect of the internet, along with
> the realization
> that the falls can lead to cash.
>
> "Statistics tell me that we are only sampling a
> portion of a much larger
> asteroidal debris field in crossing earth orbit."
>
> I don't know if the intersections of the Earth with
> either cometary or
> asteroidal debris streams would necessarily be annual. What
> you probably
> would need to do would be to sort known falls by type,
> subtract days between
> falls, and then look for multiples. That's about as
> far as I can take this
> kind of analysis now, and I know it's less than what
> would be needed.
>
> Imagine the result if you will: "Ah, March 12. Well
> tonight perhaps a nice
> pallasite is going to fall at 3 in the morning. Time to
> start up the old
> fireball survey system. Wonder what it will have for us
> tomorrow morning?"
>
> E.P. Grondine
> Man and Impact in the Americas
>
>
>
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Received on Wed 18 Feb 2009 04:31:50 AM PST