[meteorite-list] Suspected Meteorite Hits Illinois Home

From: Matson, Robert <ROBERT.D.MATSON_at_meteoritecentral.com>
Date: Mon, 5 Mar 2007 15:52:15 -0800
Message-ID: <A8044CCD89B24B458AE36254DCA2BD07032A1190_at_0005-its-exmp01.us.saic.com>

Hi All,

Another mystery:

> A chunk of metal that crashed through the bedroom window of David
> and Dee Riddle just after 9:30 a.m. appears may be a meteorite but
> it also could be a piece of space junk according to preliminary
> analysis by several Illinois State University geology professors.

"Through" a window rather than through the roof? That means that the
object had a significant portion of its motion in a horizontal
direction, which is difficult to explain for a metallic object
that supposedly came from outside the atmosphere -- unless it
ricocheted off a tree or another object outside the window. I
wonder what the angle is (from vertical) between the desk impact
location and the hole in the window?

> Because of the steep entry angle into the house and the speed the
> object crashed into the house, Nelson said is definitely was not
> a rock thrown at the window.

Well, the picture they show of the hole in the desk is on the desk
edge that I would assume was furthest from the window (given the
orientation of the computer monitor). So even if the desk is only
two feet deep and was butted up against the wall with the broken
window, trigonometry tells you that the entry angle was no
shallower than 20 degrees from vertical -- and that assumes a
desktop 30" off the floor in a room with a window as high as
8 feet off the floor. If the window is only as high as 7 feet,
the minimum angle increases to 24 degrees.

For comparison, if you fired a projectile horizontally at 500 mph,
7 miles above the earth (think metal falling off an airplane),
but did it in a vacuum, the projectile would hit the ground at
over 1600 mph, but an angle of only 18 degrees from vertical.
Adding back the atmosphere will only serve to slow down the
projectile and make its entry more vertical.

Now, given the object's odd shape, some amount of lift is possible,
but not enough (from the picture I've seen) to make the entry
angle 20 degrees from vertical. Conclusion: either this object
hit a tree or some other object before caroming through the
window, or it did not originate at a high altitude, let alone
space.

--Rob
Received on Mon 05 Mar 2007 06:52:15 PM PST