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More Moon and Mars

June 28, 2011

Showers of any kind are rare in the Egyptian desert. But the people of El-Nakhla, near Alexandria, were especially surprised when a shower of black stones fell on their village 100 years ago today. Some were tiny slivers, while others were as big as a fist. Some buried themselves up to a foot deep in the desert sands. And one supposedly killed a dog -- a story that's grown in stature over the years, although there's no confirmation.

The stones were part of a space rock that exploded as it zipped through the atmosphere. Its origin? The planet Mars.

Egypt's leading geologist visited the site soon after the shower. He led an effort that collected about 40 samples. Most of them were coated with a black crust -- the result of heating during the brief plunge into the atmosphere. Collectively, the samples are known as the Nakhla meteorite.

Decades later, scientists discovered that Nakhla came from Mars. Tiny bubbles of gas in the meteorite match the composition of the Martian atmosphere.

Nakhla is about 1.4 billion years old. It contains minerals that tell us it formed in a watery environment. It was blasted into space when an asteroid slammed into Mars -- setting a chunk of the Martian crust on a collision course with Earth.

Mars is climbing into view in the dawn sky. It looks like a bright orange star. Tomorrow, it's to the upper right of the crescent Moon. The true star Aldebaran, which also shines orange, is closer to the Moon.


Script by Damond Benningfield, Copyright 2011


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