Like shooting stars? If so, mark your calendar for the overnight hours of August 12-13th, when the annual Perseid Meteor Shower (pronounced PER-see-id), will be at its peak. It’s considered one of the best meteor showers of the year! What’s in store for 2021? Read on!
What Is the Perseid Meteor Shower?
The Perseid Meteor Shower is an annual shower whose name derives from the constellation of Perseus, from which it appears to emanate. Almost all meteors seen on these nights will be members of the Perseid stream; tiny bits of space debris that were shed by Comet Swift-Tuttle over past centuries. Each meteoroid slams into Earth’s upper atmosphere at 37 miles per second, creating an incandescent trail of shocked, ionized air. It’s this hot trail, not the tiny meteoroid itself, that we see.
At the shower’s maximum, these meteors seem to diverge from a small area in northern Perseus. This is so far north that it’s already above the northeast horizon for most of the country when darkness falls. Hence some Perseids are seen as early as 9 or 10 o’clock. But only after midnight, when the radiant is high in the sky and we have been turned by the Earth onto its forward-moving side, do their numbers really begin to increase. Anyone at mid-northern latitudes who can escape bright city lights might see the oft-advertised 60–90 meteors each hour that makes this shower so gratifying.
Some of the Best Shooting Stars of the Year?
Another reason the Perseids are popular: they are swift, bright, and colorful. Most are in the range of magnitude +2 to +2½. Fainter meteors are white or yellow; brighter ones are bluish-green. About one-third, including all the brightest, leave luminous trails (technically called trains), a few of which may be spectacular, persisting for many seconds. A few might end in flares or bursts resembling a strobe, capable of casting shadows.
How To Watch The Perseid Meteor Shower
No two persons prepare for a meteor vigil the same way. Expect the effective low temperature to be far below what local weathercasters predict. When you sit quite still, close to the rapidly cooling ground, and the air is damp, you can become very chilled. It helps to have had a late afternoon nap. A reclining lawn chair, heavy blankets, sleeping bags, and pillows are all essential equipment. Some food and non-alcoholic drink will help keep you comfortable. It also helps to have a companion to help you watch the sky (“shower” with a friend?).
And if the peak night is cloudy, don’t fret—the Perseids can be seen on multiple nights. Rates are about half to one-quarter of the peak for one or two nights before and after. In fact, the first forerunners of the shower have been known to show up as early as July 20th, and the last stragglers have been seen as late as August 24th.
What’s In Store For 2021?
Unrolling a sleeping bag in the open air is a fine way to enjoy summer meteor showers. Each year, many unsuspecting campers probably receive a startling initiation into astronomy by looking up at the sky when the Perseid meteors are near maximum. Peak activity in 2021 is expected during the overnight hours of August 12-13 and the Moon will be in a wide waxing crescent phase and will set at around 10 p.m., leaving the rest of the night dark for watching for these bright, swift streaks.
Most of these “shooting stars” would be identifiable as the Perseids because their paths, extended backward along the line of flight, would intersect near a point on the border between Perseus and the “W” of Cassiopeia. This lies low in the northeast around 10 in the evening but climbs almost overhead by the first light of dawn. That’s why although meteors numbers will be low during the evening hours, you’ll notice a crescendo in hourly rates of 45 to 90 in the after-midnight hours.
Another August Shower
Be on the lookout for outstandingly bright meteors called fireballs, or even one that might pop like a strobe along its path, known as a bolide. Lesser numbers of Perseids will be visible for a few days before and after the peak.
As August progresses, with the Perseids on the wane, activity will give way to other showers. The Kappa Cygnid display will peak between August 18th and 20th. Although this shower produces only a handful of meteors each hour, some of them are flaring fireballs. Unlike many other showers, the Kappa Cygnids are associated with no known comet. Best viewing is in the early evening, when the constellation of Cygnus, the Swan is nearly overhead.
Joe Rao is an astronomer and contributes regularly to the Farmers' Almanac.