Time lapse image taken during the Perseid meteor shower in 2009. When viewing a meteor shower with your eyes, you will usually see only one meteor at a time, about once per minute on average. The time lapse image reveals how the Perseids seem to radiate from a common point, the shower's "radiant point." (NASA/JPL)
If you're stir-crazy from months of social distancing and sheltering at home, we have some good news: the Perseid meteor shower is back! It's a chance to break from your routine, get outside, and see something beautiful in the night sky.
Among the most reliable annual showers, the Perseids offer an abundance of bright meteors — visible despite urban light pollution or moonlight.
The Perseid shower typically lasts from July 23 to Aug. 22, though the peak activity takes place between Aug. 11 and 13. The best time to see them is during the early morning hours of Wednesday, Aug. 12.
Meteor watching is best done from a place with dark skies, away from city lights. Urban light pollution will outshine the fainter streaks and reduce the number of meteors you can spot. But at the Perseids' peak rate of 50-60 per hour, you shouldn't have to wait long to glimpse one of the brighter meteors.
After midnight, find a safe viewing location with an unobstructed view of the northeastern horizon, to the left of where the sun normally rises, and get comfortable. (To get it dialed in, there are free compass apps you can download for your phone.)
The meteors will radiate from the direction of their namesake constellation, Perseus, above the northeast horizon. Center your view on Perseus, located below the more familiar "W" of the constellation Cassiopeia, but pay attention to as much of the sky as you can, since a meteor may appear at any time, anywhere in the sky.
This year the Third Quarter moon will be in the sky for most of the morning hours, rising around 12:30 a.m. on Aug. 12. Though not as bright as during its Full phase, the moon's light will compete somewhat with your meteor watching, but it certainly won't spoil the show.
Since the moon doesn't rise until 12:30 a.m., there's a half-hour window just after midnight when the sky should be quite dark, so that may be the best time for meteor watching. But, you'll be able to see the Perseids until dawn.
If you miss the first night, you can still catch the show on the following morning of Aug. 13. The waning moon will be less bright, and will rise later, around 1 a.m., offering an even bigger window to see some Perseids flash across the sky.
Even if you live in the city, you may know a good place, not too far away, where you can escape from the urban lights and find darker skies. Wherever you go, consider taking a buddy and a flashlight, and remember to stay safe.
A few locations around the Bay Area include Mount Diablo, the Sunol area, Henry Coe State Park in the South Bay, and along Skyline Boulevard on the Peninsula. There are great spots in the less populated Sonoma and Napa areas as well. Of course, be sure to check if there are any COVID-19 closures or restrictions in any location you choose.
And though there are some good coastal areas away from city lights, they are often foggy this time of year.
You Snooze, You Lose
Meteors, or "shooting stars," are caused by tiny specks of rock and metal from space burning up in Earth's atmosphere. Most meteors are incinerated at altitudes of 40 or 50 miles above Earth's surface and never come close to the ground.
A meteor shower occurs when the Earth moves through a stream of dust particles left behind by a comet that cruised near Earth at some time in the past.
It is after midnight that we are on the side of the Earth that's moving into the dust stream, allowing us to see the meteors.
Think of riding in a car traveling down a freeway, when suddenly the car plows through a swarm of flying bugs. You only see the bug streaks on the side of the car facing its direction of motion — the windshield — and not the rear window.
Each of the annual meteor showers — the Perseids, the Leonids, the Geminids, and others — come from a dust stream left behind by a different comet. We see a given meteor shower at the same time each year, when the revolving Earth returns to the point in its orbit where the dust stream is located.
The comets that leave these dust streams originate far out in space, in the cold regions of the solar system around Neptune and beyond, and only pass by Earth every few decades or centuries.
The parent comet of the Perseids is called Swift-Tuttle, named after Lewis Swift and Horace Parnell Tuttle, who discovered it in 1862. Swift-Tuttle orbits the sun once every 133 years, and last passed close to us in 1992. At its greatest distance from the sun, the comet travels farther out than dwarf planet Pluto, located in the Kuiper Belt at the edge of our solar system.
Think about this as you wait to see your next shooting star: every meteor you are privileged to see is an ancient grain of dust that a comet carried to us from billions of miles out in space. After traveling through space for billions of years, since the solar system was formed, you see it for an instant, and then it's gone in a flash!
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