Precinct 333

Sunday, March 13, 2005

Science Geek Story

When we moved back Stateside from Guam in 1976, our family drove across country from San Francisco to San Diego, on to Washington, DC, north to Rhode Island, and finally on to Great Lakes, Illinois. The reason for the circuitous trip was to visit family members around the US, and also to allow we boys to see something of the US. One of my favorite stops was the Barringer Meteorite Crater in Arizona. I was fascinated by the site of that big hole in the ground, and have kept track of articles about it over the years.

Now we have some scientific speculation on why the crater is the size it is, and why it didn't melt much of the rock in the area when it struck.

Using computer models for how such objects would interact with the atmosphere, Melosh and astronomer Gareth Collins of Imperial College London concluded that the 300,000-ton, 130-foot-diameter meteor fractured before it hit the ground, with about half of it dispersing into small fragments.

The remaining half struck the ground at a speed of 26,800 mph, about 10 times the velocity of a bullet fired from a high-powered rifle, but not fast enough to melt large quantities of rock, the scientists reported this week in the journal Nature.

The intact fragment exploded with the energy of at least 2.5 megatons of TNT, they said.

I'll have to get that copy of Nature magazine to read the article.


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