Thursday, June 30, 2011

Mars Meteorite Strikes Egypt - 100 years ago

Exactly a century ago, on June 28, 1911, an explosion shook the Nakhla region of Alexandria in Egypt at 9 a.m.

Soon after, around 40 chunks of meteorite debris from the high altitude blast rained down. 22 pounds (10 kilograms) of the bolide were recovered by witnesses of this cosmic event.

The Smithsonian received two samples of the Nakhla meteorite the following August and then acquired a larger 480 gram (one pound) piece in 1962 (pictured top).

By the 1970's, the Smithsonian had collected 650 grams (1.4 pounds) of the meteorite.

The Nakhla meteorite fragments -- dubbed "Nakhlites" -- are now known to originate from Mars.

Even better than that, scientists have been able to narrow down to where on the Martian surface the original meteoroid came from.

Nakhlites are igneous rocks rich in the mineral augite.

This indicates the original rock formed as a basaltic magma approximately 1.3 billion years ago, when Mars was volcanically active.

Through careful analysis of the rock's crystalisation ages and crater-count chronology of different regions on Mars, the Nakhla meteorite most likely formed in the ancient volcanic regions of Tharsis, Elysium or Syrtis Major Planum, according to the Smithsonian website.

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