Allende Meteorite

The Allende meteorite fell as a shower of stones after breaking up in the atmosphere at Chihuahua, Mex., near the village of Pueblito de Allende, in February 1969. More than two tons of meteorite fragments were collected. Fortuitously, the Allende meteorite fell shortly before the first rock samples from the Moon were brought to Earth by Apollo astronauts, and its pieces were analyzed by many scientists in preparation for handling lunar rocks.

The Allende meteorite, which is classified as a carbonaceous chondrite, consists of large, irregularly shaped white inclusions and rounded chondrules in a dark matrix. The inclusions are composed of minerals believed to have condensed at high temperatures from a gas having the composition of the Sun, and their time of formation is older than that of any other known solar system material. The inclusions in Allende and other carbonaceous chondrites are thought to be the earliest-formed solids in the solar nebula.

One of the earliest instances of a meteorite fall on record is that of the Ensisheim meteorite, which descended from the sky onto a wheat field in Alsace (now part of France) in 1492. Maximilian I, who was proclaimed Holy Roman emperor soon afterward, assembled his council to determine the significance of this event; their verdict was that the meteorite was a favourable omen for success in Maximilian's wars with France and Turkey. Accordingly, Maximilian ordered the Ensisheim stone to be placed with an appropriate inscription in the local parish church. The meteorite was fixed to the wall with iron crampons to prevent it from wandering at night or departing in the same violent manner in which it had arrived. It resides in the town of Ensisheim today, although visitors in the intervening centuries chipped off all but 56 kg (123 pounds) of its original 127-kg (280-pound) mass. The Ensisheim meteorite is classified as an ordinary chondrite.

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