The best fireworks visible on Earth are set off by distant comets in the night sky. This year’s Perseids, as the periodic meteor shower is called, is going to be among the best that the comet Swift-Tuttle has ever set off.
A meteor shower is a celestial event caused when small particles enter Earth’s atmosphere and burn up. In this case, as the Earth crosses floating debris from the comet Swift-Tuttle’s previous passes, we witness the Perseid meteor shower, named after the Perseus constellation that appears to be the point of origin for the light show.
The Perseids have already begun. But the best viewings start tonight (Aug. 11). It doesn’t matter where on Earth you live. According to NASA, “The best way to see the Perseids is to go outside between midnight and dawn on the morning of Aug. 12. Allow about 45 minutes for your eyes to adjust to the dark. Lie on your back and look straight up. Increased activity may also be seen on Aug. 12-13.”
NASA has a livestream, if you’re in a place that’s not good for stargazing or don’t want to venture out.
Indeed, this year’s Perseids will be particularly spectacular because Jupiter’s gravity has pushed the comet’s debris towards the Earth. Instead of traveling through the edges of the comet trail, as Earth usually does, we will whizz closer the middle of it and thus see more cosmic debris burning up in the sky. On Thursday night, as many as 200 meteors per hour could be visible from Earth. That number will half every subsequent night, as we leave Swift-Tuttle’s trail behind.
“The meteors you’ll see this year are from comet flybys that occurred hundreds if not thousands of years ago,” said Bill Cooke of NASA’s Meteoroid Environments Office. “And they’ve traveled billions of miles before their kamikaze run into Earth’s atmosphere.”
“It scares you to the bone when you see it coming across,” Jackie Faherty, an astronomer from the American Museum of Natural History, told the New York Times. “If you get just one, it will be embedded in your vision for all time. I don’t think you forget things like this.”
Nope. Although Perseid meteors travel at the speed of 132,000 mph (212,000 kph), they burn up some 50 miles (80 km) above the Earth after reaching a temperature of 10,000 degrees Fahrenheit.
However, future generations may have more to worry about. The comet that is responsible for the Perseids has been described by some astronomers as the “single most dangerous object known to humanity.” Swift-Tuttle’s orbit is 133 years, and its next closest brush with the Earth will be in 2162. It won’t get within spitting distance of the Earth again until the year 4479, when the probability of a collision is one in a million. That might seem low, but given the comet’s size—much larger than what was thought to have caused the extinction of dinosaurs—it could cause total devastation.
Enjoy the show!