[meteorite-list] Mystery object in photo

From: Chris Peterson <clp_at_meteoritecentral.com>
Date: Tue Dec 7 19:48:35 2004
Message-ID: <0dc601c4dcbf$a23fc910$f551040a_at_bellatrix>

The angle observed for the fireball trajectory is largely unrelated to the
angle the meteorite will strike the ground. It is perfectly possible for the
impact angle of a meteorite to be in the opposite direction of the entry
angle, since the final angle is determined primarily by wind.

The Peekskill fall is not difficult to model. The recovered piece was
falling nearly vertically at the end. It traveled 50 km after the end of
ablation because at that point its path was nearly horizontal, and it was
still at about 3 km/s. But that forward velocity was quickly lost to
atmospheric drag.

I don't know the details of the Nakhla fall, but I would be suspicious of
witness reports giving 30 degrees from the horizontal. There is really no
mechanism to explain how any ballistic object that has slowed to a few km/s
while still 30 km or more high could have significant horizontal velocity
when it reached the ground (unless it were falling in a hurricane!)

Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com


----- Original Message -----
From: "Ron Baalke" <baalke_at_zagami.jpl.nasa.gov>
To: "Meteorite Mailing List" <meteorite-list_at_meteoritecentral.com>
Sent: Tuesday, December 07, 2004 4:30 PM
Subject: Re: [meteorite-list] Mystery object in photo


>
> >
> > This series of photos made the rounds a few weeks ago -- it definitely
> > is not a meteorite fall. Simplest reason: it doesn't fall vertically.
> >
>
> Peekskill and Nakhla didn't fall straight down either. Peekskill travelled
> an additional 50 km AFTER ablation had ended. Nakhla was observed to
> hit the ground 30 degrees from the horizontal.
>
> Nevertheless, I don't think it is a meteorite. Probably just a bug
> that flew in front of the camera. That would explain the bluriness
> in the trail. And the 'explosion' would be an overexposure of the bug
> from the camera flash.
>
> Ron Baalke
Received on Tue 07 Dec 2004 07:48:16 PM PST