Cover image of a “bolide” meteor passing near the Pleiades star cluster by Juan Carlos Casada.
Wild headlines online have led many a prospective meteor-watcher into the cold on the lookout for “hundreds” of “shooting stars,” but Earth’s meteor showers remain tantalizingly difficult to observe. Here’s everything you need to know about meteor showers, and which ones to try for in 2021.
What are meteor showers?
As Earth orbits the Sun, it sometimes passes through clumps of dust and debris left in its orbital path. This debris comes from comets that entered — then exited — the solar system, sometimes many decades ago. When you see a “shooting star”, you’re watching tiny meteoroids — or pebbles hitting Earth’s atmosphere — releasing photons of light as they discharge. Meteor showers are annual events that can allow you to see anywhere from 5 to 150 “shooting stars” per hour.
Understanding meteor showers
There’s a lot to unpack if you’re to truly understand what you’re about to get yourself into. Even the very terms meteor “shower” is rather misleading. Very rarely is anyone ever “showered” with meteors! Astronomers quote the zenithal hourly rate (ZHR), the rate at which meteors could be spotted directly above you in the night sky under ideal conditions. In short, you need a clear and very dark sky far from light pollution if you’re to see anywhere near the number of meteors suggested by the ZHR. You’ll also need to be very patient, have your eyes to the skies almost permanently, and have a meteor shower peak during the darkest hours where you are. Most such displays are best viewed after midnight when your location is turning to face the oncoming debris, which will therefore create faster-moving, brighter meteors.
What makes a meteor shower “favorable?”
The biggest light polluter in the night sky isn’t streetlights or skyscrapers, but the moon. Even if you’re in the middle of a national park, a desert or on a high mountain, if there’s a bright moon, then the sky will be virtually empty of meteors even if the year’s biggest shower is underway. In 2021 that means only three of the 12 regular meteor showers will take place in moonless night skies.
Moonless meteor showers in 2021
Chasing every single meteor shower in 2021 would be a mistake. These are the meteor showers you need to know about – and plan for – in 2021. Luckily, the list includes the year’s most popular meteor shower, the Perseids. However, while the peak nights are what to aim for, there’s always a chance of bright meteor on the nights just before and after, so if skies are clear where you are it’s wise to make plans.
Perseid meteor shower (Aug. 12 to 13, 2021, ZHR 110)
The northern hemisphere’s most famous meteor shower is easily the most favorable in 2021 due to a new moon only a few days before, on Aug. 8. Figure on watching from midnight through dawn, and keep an eye out for bright meteors that leave bright “trains” in their wake. Go camping, but book well ahead!
Draconid meteor shower (Oct. 8 to 9, 2021, ZHR 10)
With a new moon on Oct. 6, the Draconids will get a lot of attention, though the number of meteors you’re likely to see is far lower than for the Perseids. However, since the Draconids are associated with the circumpolar northern sky (which always remains above the horizon in most northern latitudes), you don’t have to wait for midnight to start watching for meteors. Make a plan to watch from twilight through midnight. The Draconids may not be prolific, but they are convenient!
South Taurid meteor shower (Nov. 4 to 5, 2021, ZHR 10)
This minor meteor shower coincides with a new moon, though in fact its peak is so spread-out that “minor” is the key takeaway for this meteor shower. The main reason to watch the South Taurids is to catch a “fireball event” in a dark sky. Fireballs are bright meteors that flash as bright as Venus and sometimes leave a “train.”
Meteor-spotting is not easy and requires both dedication and luck with clear weather. However, by checking with the moon, you can easily trim-down the annual list of prospective meteor showers to prioritize only those that will give you the best chance of having “shooting stars” in your eyes.
Learn more details about meteors and about 2021’s meteor shower prospects at the American Meteor Society where you can also report any “fireballs” you witness to their website.