The Sky Is Falling, the Sky Is Falling!

Meteor watching doesn’t require any special equipment at all, but is best enjoyed when the moon is out of the way. Fortunately, this year’s Leonid meteor shower peaks November 17, right around New Moon. If the sky is clear, you could be in for a treat.

Leonid meteors start out as specks of dust and debris ejected by Comet 55P/Tempel-Tuttle, which orbits the Sun every 33 years. Over time, these particles spread out along the comet's orbit. Every November, Earth passes through this stream of cosmic debris.

These particles hit our atmosphere at 147,000 mph and vaporize in the upper atmosphere from friction with the air. This produces the streaks of light in the sky we call meteors. Leonids are swift, dashing meteors that often have flares at the end of their trails. Some of them leave behind persistent trains, like tiny vapor trails from jets.

By the way, when these particles are flying through space they are known as meteoroids. If they survive the fiery ride through the atmosphere and hit the ground they are called meteorites.

This meteor shower is called the Leonids because if you trace all the shower's meteor paths backward, they appear to radiate from a point in the constellation Leo the Lion. This point of origin is known as the radiant. The Leonids radiant is very near Gamma Leonis.

Observers are normally rewarded with 20 to 30 meteors per hour, but the Leonids have surprised us in the past. In 1833 the Leonids shower was actually a meteor storm, with a hundred thousand meteors per hour putting on a show. In 1966 observers in the US saw Leonids falling from the sky like rain, at a rate of thousands per minute. In 1998, the year of Comet Tempel-Tuttle’s last return to the inner solar system, there was a brilliant display.

The peak of activity coincides with when the Earth passes through the thickest part of the debris trail left behind by Tempel-Tuttle. Predicting just when that will happen is difficult, but predictions seem to get more accurate each year. If you’re lucky you could see hundreds of meteors. If not, the few dozen you see will be reward enough for some time well spent under the stars.

I’m willing to go out on a limb and make a prediction. If you don’t go outside and look up in the next few days, you won’t see any meteors.

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