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Geminid Meteors

December 13, 2010

The Moon and the planet Jupiter put on an impressive display this evening. They're in the south at nightfall, with brilliant Jupiter just below the Moon.

And after they set, around midnight, another impressive display could light up dark skies: the Geminid meteor shower, which should be at its best tonight.

The Geminids are bits of debris from an asteroid known as 3200 Phaethon. As it approaches the Sun, it gets so hot that minerals at its surface may crack, expelling bits of rock and dust into space. Radiation from the Sun blows away the smaller grains, but the larger ones spread out along Phaethon's orbit. When Earth crosses this orbital path, some of the particles plunge into our atmosphere, forming the incandescent streaks known as meteors.

Phaethon itself may be a fragment of a larger asteroid, known as Pallas. There's a "family" of about 70 small asteroids that seem to be related to Pallas. They may have been blasted into space when a smaller body rammed into Pallas. Phaethon's orbit and its surface composition share some qualities with the asteroids that form the Pallas family.

A recent study says that objects ejected in a collision between Pallas and another asteroid can spend millions of years in stable orbits around the Sun before hitting the Sun. So in the distant future, the parent of the Geminid meteors could end its own life as a brilliant meteor blazing into the Sun.


Script by Damond Benningfield, Copyright 2010


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