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Spawned by an Asteroid

The Geminid meteors are unique

This week’s celestial highlight is the annual Geminid meteor shower, which peaks late Saturday and before sunrise Sunday. This coincides with the rising waning moon, which just shy of last-quarter still shines quite bright. Fortunately, the Geminids are some of the brightest “shooting stars,” and given patience and a dark spot away from urban glare, you could still expect to see one or two meteors each minute. Plus the Geminids generate a fair number of meteors for several days before and after the peak.
    Like all meteor showers, the Geminids occur as earth passes through a trail/stream of cosmic dust and detritus. As these bits of rock and ice hit our atmosphere, they burst into flames. While the end results are the same, the source of the Geminids’ debris trail is unique. In every other case, these trails of debris are left by comets orbiting the earth in the same way as the planets. The source of the Geminids, however, is a five-kilometer asteroid, known as 3200 Phaethon, that passes between the sun and Mercury every 1.4 years.
    And where comets orbit the sun with a long tail releasing a trail of flotsam, 3200 Phaethon has no tail but somehow produces a trail of debris anywhere from five to 500 times larger than any spawned of comets. Instead of a tail of its own releasing fragments as it’s heated by the sun, 3200 Phaethon pulls bits of dust and debris into its wake as it travels the solar system in a way astronomers are still trying to explain.
    Many meteor showers have been seen since the dawn of civilization, but not the Geminids. They were first noted in 1862 — simultaneously — by an American and a British astronomer, who each recorded an average of 14 meteors an hour. Year by year, that number grew, even as astronomers searched for the shower’s source. Then in 1983, armed with the Infrared Astronomical Satellite, they found 3200 Phaethon to be the parent of the Geminids. By that time, the shower had grown to an average of 120 meteors an hour under good conditions!
    With clear skies you can see the spawn of 3200 Phaethon anywhere in the dark sky, but all point back to the constellation Gemini.
    While you’re at it, look for Jupiter rising in the east-northeast around 10pm and high in the south come dawn. Saturn rises just ahead of the sun in the east-southeast. And Venus and Mars are both visible after sunset.