If you’re outside after dark this week in the northern hemisphere you might just spot a particularly bright shooting star coming from the east. It’s likely from the Leonid meteor shower, which is active from November 6 to November 30, but at its most prolific—in terms of the number of shooting stars per hour—on and around Monday, November 18.
What do Leonid meteors look like?
Named after their radiant point in the constellation of Leo, the lion, Leonids are mostly fast, bright meteors with a persistent “train” behind each that can be visible for a second or more. They’re some sight and, just occasionally, a “Leonid meteor storm” can occur. However, that’s not predicted to happen this week.
What causes shooting stars and meteor showers?
Shooting stars come from streams of particles of dust and debris—meteoroids—left in the solar system by passing comets. As Earth orbits the sun, those particles collide with its atmosphere and heat-up as they disintegrate, causing a streak of light in the sky. When that stream of dust and debris is particularly dense, it’s called a meteor shower. Since Earth’s orbital path around the sun doesn’t change, meteor showers happen every year on the same dates, almost like clockwork.
The Leonids are faster and brighter than most shooting stars because the stream of meteoroids that causes them is orbiting the Sun in the opposite direction as Earth. They strike Earth’s upper atmosphere full-on at 160,000 mph/257,000 kmh, many many times faster than a speeding bullet.
Where do the Leonids come from?
The cause of the Leonid meteor shower stream is comet 55P/Tempel-Tuttle. It’s one of the shortest period comets astronomers know of, and it buzzes into the solar system to loop around the sun every 33 years. However, it’s currently 19 astronomical units (au) from Earth (around as far as Uranus) in the direction of (but far beyond) the planet Venus. According to NASA, its nucleus measures only about 2.24 miles/3.6 kilometers across.
When is the next Leonid ‘meteor storm’ predicted?
Defined as an event where 1,000 shooting stars are visible each hour, a Leonid meteor storm appears to happen every 33 years. 1,000s of Leonids were seen in 1833, with smaller storms in 1866, 1966, 1999 and 2001, mostly when 55P/Tempel-Tuttle was in the solar system. The 1833 storm produced 100,000 meteors per hour and in 1966 people saw thousands of meteors per minute for 15 minutes, according to NASA.
The 1999 and 2001 storms produced about 3,000 per hour. However, though Earth is not predicted to encounter any dense clouds of debris until 2099 according to the American Meteor Society, when comet 55P/Tempel-Tuttle returns in 2031 there could be in excess of 100 shooting stars per hour.
Best time to look for Leonids
Although the early hours of November 19 would normally be the best time to view that’s only because the radiant constellation of Leo (where the shooting stars appear to come from) is high in the sky and your location will be firmly on the night side of Earth, so as dark as it gets. However, this year a waning moon gets in the way of all that. Although you could try looking at 2:00 a.m. and standing with your back to the moon, you would also be blocking the origin of the shooting stars. So this year’s it’s best to look before the moon rises. So that’s from sundown through about 10 p.m or 11 p.m. for the northern hemisphere on November 18. Since the moon is actually in Leo itself, Leo won’t have risen, and so there will be fewer than the quoted 15-per-hour. However, if you look generally east you’ll have a decent chance of seeing a bright Leonid meteor or two.
Stargaze while you’re waiting
Shooting star-hunting can be a thankless task and does require a lot of patience. The best way to treat meteor showers is as an opportunity to go stargazing. You’re in luck because if you look east about 10 p.m. on November 18 you’ll see the stars of winter rising, notably the “Winter Circle” and the “Winter Triangle.”
Wishing you clear skies and wide eyes.