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(meteorobs) clustering
This is kind of funny. I did a science fair project in 1968-9 on clustering
of meteors. Thanks for placing info
Dr. Eric Flescher (KCStarguy@aol.com)
member, Astronomical Society of Kansas City (ASKC)- Solar System Ambassador
2002- JPL-(Jet Propulsion Lab) and NASA
====================================================== ORIGINAL MESSAGE...
>Date: Mon, 24 Dec 2001 09:47:12 -0800
>From: Chris Crawford <chriscrawford@wavedot net>
>Subject: Re: (meteorobs) Clustering (a new approach?)...
Let's consider the formation of that 70 km sphere of meteoroids. We know
that streams as old as 300 years can still produce big storms, so let's
assume that the average age of a storm meteoroid is 150 years. Let's further
assume -- for no good reason -- a "half-life" for breaking up of half that
time. Thus, the average meteoroid we find broke up 75 years ago. For its
descendents to remain within a 70 km sphere, they'd need to have a relative
velocity of about 1 km/year, which amounts to 32 micrometers per second.
That strikes me as a very low relative velocity. Of course, there will be
many meteors that break up much more recently, and so could still remain
within a 70 km sphere with much higher relative velocities. But the
conclusion I draw from this is that the descendents of a broken-up meteoroid
will rapidly spread out to distances greater than the average distance
between two unrelated meteors. This is going to be hard to prove.
By the way, you mention that we'd be looking for the group to appear to
sweep from east to west across the surface of the earth. I know that this is
counterintuitive, but the motion of the streamer across the surface of the
earth is dominated by the orbital motions, not the rotational motion. In
particular, it is determined by the difference between the earth's orbital
velocity and the meteor shower's apparent velocity -- which in the case of
the Leonids, is very small but runs from southwest to northeast.
Chris
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