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[log in to unmask] writes:
>I have two follow-up questions that, admittedly, I ask out of my own
>curiosity and for my own professional development. If an object of this
>size were to have a trajectory that defined a collision course with the
>Earth: 1) Would it actually reach the surface of the Earth (or would it
>burn as it passed through the atmosphere), and 2) What kind of an impact
>would it have?
>
>Hopefully, there are people on this listserv with both the expertise to
>answer these questions (of which I have no doubt), and the time to do so
>(somewhat less likely).

I can answer part of your questions.  An asteroid that is 18-50 meters in
diameter would not erode away completely due to friction with the Earth's
atmosphere.  If it stayed together, it would impact the Earth's surface.
The questionable part, though, is how dense the asteroid would be & if it
would stay together as one chunk or break apart into many chunks at some
distance above the Earth's surface.  This happened here in the Chicago
area last March (coincidentally!).  A small asteroid about the size of a
Volkswagen Beetle entered the Earth's atmosphere, travelled through for a
distance, broke apart (not sure of the height above the surface), and the
smaller pieces screamed downward and impacted the Park Forest/Olympia
Fields area.  Some chunks hit a couple of houses at about 200 miles per
hour.  Others harmlessly hit fields & made little craters.

As for the size of crater an 18-50 meter chunk would make...let me find
out from one of our astronomers...I'll post that to the list-serv sometime
this afternoon (I hope).

Michelle

Michelle Nichols, Senior Educator
Adler Planetarium & Astronomy Museum
1300 S. Lake Shore Dr.
Chicago, IL  60605
312-322-0520
312-322-2257 (fax)
[log in to unmask]
http://www.adlerplanetarium.org

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