Tuesday is shaping into a big night for star gazers, since that's when the 2009 Leonid meteor shower will peak, giving those in Asia in particular something of a spectacular light show. The fireworks will be further helped by the fact that the moon will be in its new phase. NASA's Meteoroid Environment Office predicts between 20 to 30 meteors per hour over the Americas, and 200 to 300 per hour over Asia. A truly spectacular meteor shower could produce as many as 1000 meteors an hour, but such "storms" are quite rare.
Lest folks are a bit jumpy after seeing 2012 over the weekend, the Leonids, or any other meteor shower, will not portend the end of the world as we know it. Meteors are not the same thing as asteroids. They're just bits of cosmic debris traveling at high speeds, and they are usually quite small, on a par with a grain of sand. So they disintegrate when they hit Earth's atmosphere and never reach the ground. The light show is the result of that process. Occasionally a larger fragment will hit the Earth: those are called meteorites. (And as any fan of superhero mythology knows, finding a meteorite fragment from the former planet Krypton gives you power over Superman. Insert evil cackle here.)
In the case of the Leonids, the debris comes from the Comet Tempel-Tuttle, which returns to the inner solar system every 33 years, leaving a stream of dust in its wake. Astronomers are pretty good about predicting when the Earth's orbit will cross a debris stream and encounter debris from the constellation Leo (it usually happens in November); they just can't predict how intense the shower will be.
In honor of tomorrow's cosmic spectacle, I thought I'd honor the two men who discovered this particular comet: German astronomer Ernst Temple, who observed the object on December 19, 1865, and American astronomer Horace Parnell Tuttle, who saw the same object independently a few weeks later on January 6, 1866. (Actually, another German astronomer named Gottfried Kirch observed the comet way back in 1699, but he didn't recognize it as such.)
Both Temple and Tuttle were avid comet hunters, and Temple had at least one other comet named after him, 9P/Tempel, which according to Wikipedia was also the target of the NASA probe Deep Impact in 2005. Tuttle's comet hunting activities were sharply curtailed by the American Civil War; he served in the 44th Massachusetts Voluntary Infantry and ended up with a commission in the US Navy. He saw 9P/Tempel from the deck of the monitor U.S.S. Catskill in 1864, and made his co-discovery of Comet Tempel-Tuttle at the Naval Observatory in 1866.
So if you're one of the folks who'll be stargazing in the wee hours on Tuesday, remember the two men who first discovered the parent body of what you're witnessing. And also ruminate on the sheer time scale of the comet, which has been making its 33-year orbital return for so long, its history probably dwarfs that of the human race.
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