The Perseid meteor shower is back. This year, the annual sky show will peak overnight Aug. 12-13, when — weather permitting — skywatchers should be able to see about 15 to 20 shooting stars per hour in the night sky.
The Perseids this year will have to compete with light from the full moon, which tends to wash out the short-lived streaks of light the meteors create. In years when there’s no moonlight, NASA says, the Perseids typically produce more than 60 shooting stars per hour.
But the show is worth taking in despite the less-than-ideal conditions, said Bill Cooke, head of NASA's meteoroid environment office at the Marshall Space Center in Huntsville, Alabama, and a well-known meteor expert. "That's still more [meteors] than any shower you'll see except for the Geminids," he said, adding that the Perseids are known to produce unusually bright meteors known as fireballs. "It's still worth going out to look at the Perseids. It just won't be as good because of the moonlight."
The Geminid meteor shower, which returns each December, is the only shower that produces meteors at a higher rate than the Perseids, Cooke said.
The Perseid meteors are so named because they appear to come from the direction of Perseus, a large constellation in the northern sky. Like other meteor showers, they arise when small, fast-moving bits of debris from the tail of a comet smash into Earth's upper atmosphere. In this case the debris is moving at 132,000 miles per hour when it hits the atmosphere, and the comet is a particularly large one known as Swift-Tuttle, which completes one orbit of the sun every 133 years.
The central portion, or nucleus, of Swift-Tuttle is about 16 miles in diameter — making the comet more than two times bigger than the one that scientists believe struck Earth 65 million years ago and killed off the dinosaurs.
Luckily for us earthlings, there's no chance that the nucleus will collide with Earth.
To view the Perseids, astronomers recommend finding a dark place away from city lights, stretching out on the ground and simply looking up at the night sky. There's no need for telescopes or binoculars. Just be sure to give your eyes enough time to adapt to the darkness.
The best viewing should come just before dawn on Aug. 13, Cooke said.
If bad weather gets in the way where you are, you should be able to see the Perseids live on NASA's Meteor Watch Facebook page starting around 8 p.m. ET on Aug. 12.
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