Geminid meteor shower: why spectacular light show puzzles scientists
By now you've probably heard that tonight's the night for what is arguably one of the most spectacular meteor showers of the year, the Geminids.
The shower earns its name from its apparent point of origin, or radiant, in the constellation Gemini.
But where many meteor showers represent Earth's encounter with dust from a comet, the Geminids appear to have an odd duck of a source: an asteroid that some now call a rock comet.
And it's not clear from recent observations whether the object, known as 3200 Phaethon, is kicking off enough material to account for the intensity of the meteor shower Earth encounters.
A team of astronomers identified the debris gap in a paper published in the Astronomical Journal in November 2010. And researchers are still puzzling over it.
Although the first recorded observations of the Geminids don't appear until the early 1860s, modeling studies of the debris' orbit suggests that the stream is anywhere from 200 to 6,000 years old.
3200 Phaethon was discovered by NASA's Infrared Astronomical Satellite in 1983. Once scientists determined its orbit, the orbit closely matched with the orbit of the debris stream.
One of the asteroid's key features is its proximity to the sun at closest approach. It comes nearer the sun than any known asteroid, well inside the orbit of Mercury. This allows surface temperatures to reach 1,400 degrees Fahrenheit.
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