From: ENN Staff
Published December 3, 2013 09:12 AM

Geminids Meteor Shower Caused by Rock Comet

The Geminids are a fast, bright, and reliable meteor shower that can be observed every December (with the morning of the 14th usually marking the peak of highest intensity.) During this time, the sky fills with flashes of light shooting out of the constellation Gemini. But where exactly do the meteors come from?


Meteor showers are supposed to come from comets, yet there is no comet that matches the orbit of the Geminid debris stream. Instead, the orbit of the Geminids is occupied by a thing called "3200 Phaethon" - a five-kilometer diameter asteroid. Resembling a rocky asteroid, Phaethon swoops by the sun every 1.4 years, much like a comet would, but it never sprouts a dusty tail to replenish the Geminids.

That is, until now.




Jewitt's team believes that the dust is launched by thermal fracturing of the asteroid's crust. A related process called "desiccation fracturing" may play a role too.


Adding up all of the light STEREO saw in Phaethon's tail, Jewitt and colleagues estimate a combined mass of some 30 thousand kilograms. That might sound like a lot of meteoroids but, in fact, it is orders of magnitude too small to sustain the massive Geminid debris stream.

Read more at NASA.

Meteor shower image via Shutterstock.

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