Solely in terms of conditions, this will be a favorable year to look for these meteors, as the moon will be in a waning crescent phase and should not be much of a hindrance to meteor spotters looking for these super-fast meteors. which are ejected from Leo’s Sickle (from which the meteors get their name). Be sure to keep this in mind: this time of year, meteor watching can be a long, cold job. Expect the ambient air temperature to be much lower than the local radio or TV forecaster.
Leonid Meteors: Debris from Comet Tempel-Tuttle
Leonid meteors are debris thrown into space by Comet Tempel-Tuttle, which swings through the inner solar system at intervals of 33.25 years. With each visit the comet leaves a trail of dust in its wake. Many of the comet’s old dusty tracks litter the mid-November of Earth’s orbit, and Earth slips through this debris belt every year. Occasionally we will pass directly through an unusually concentrated dust trail or filament, which can trigger a meteor storm resulting in thousands of meteors per hour. This happened in 1999, 2001 and 2002. Since Tempel-Tuttle passed the Sun in 1998, it was in those years following its passage that the Leonids put on their best show. Since then, the comet — and its dense dust trail — have all receded far beyond Earth’s orbit and back into the outer regions of the solar system. Tempel-Tuttle reached the end of its elliptical path near the orbit of Uranus in 2014. As a result, Leonid activity has been rather sparse in recent years. The comet has since turned and is now slowly approaching the inner solar system, although it is still very far away. It is expected to be closest to the sun again in 2031. So it seems that the odds are that there is little, if any, chance of any unusual meteor activity this year. Dust from Tempel-Tuttle electrifies the sky for a few nights each year in mid-November, and this year, the traditional peak is expected on November 18. But realistically—at best—we wouldn’t expect to see more than 5 or 10 Leonids during an hour’s viewing. However, if two reputable meteor scientists are right, this year will be an unusual one. These scientists have created several models of the Leonid stream, and all indicate that Earth will cross some “rivers of debris” left behind by Comet Tempel-Tuttle.
This image is a composite of 33 Leonids recorded during the night of November 18-19, 2001. (Credit Image: Courtesy of Koen Miskotte)
Uncertain prediction
In the 2022 “Observer’s Handbook of the Royal Astronomical Society of Canada,” meteor experts Margaret Campbell-Brown and Peter Brown indicate that peak activity this year should occur at 7 p.m. EST (0000 GMT on November 18) on the evening of November 17. This is the time when Earth will pass closest to the orbit of the long-departed comet and when our planet appears most likely to encounter some remnant cometary material. This period is particularly favorable for those in central and western Europe and western Asia. But in contrast, for North American observers, Leo will still be below the horizon. they will have to wait until late after midnight to see the Leonidas. The main show is expected on Saturday morning (November 19). Model calculations by Russian meteorite expert Mikhail Maslov and his Japanese counterpart Mikiya Sato show an approximation of a dust trail thrown by Tempel-Tuttle in 1733 interacting with Earth on that date. Maslov gives 06:00 UT, Sato predicts 6:25 UT. This translates from 1:00 am. to 1:25 a.m. EST (0600 GMT to 0625 GMT), a great time for eastern North America where Leo’s Sickle will be about a third of the way up in the eastern sky and the moon will be just below the horizon. Earth will cross the 1733 stream at a distance of 89,000 miles (143,000 km) from the center. Maslov adds that “Many of the meteors should be bright, an hourly value of 250-300 seems likely despite the uncertainties.” Sato, however, is much more conservative: “Hourly rates may reach 50+ because the model suggests dust tends to be less concentrated.” Further west, for those in the central time zone, the peak comes at 12:00 AM. to 12:25 a.m. CST (1825 GMT) and the Sickle will be noticeably lower in the eastern sky. Across western North America, the only hope of spotting anything unusual might come from an “Earth Shepherd”—a meteor that passes horizontally through the upper atmosphere from a near-horizon beam. Earth’s spectacular shepherds are usually slow and bright, crossing the sky and still worth seeking out. Otherwise, little or none of this enhanced activity will be visible because, unfortunately, Leo’s Sickle will either be on the horizon or still have to rise. There is a final possible ascent of Leonid on November 21st at 15:00 UT, from debris dropped by the comet in 1800. Timing favors Hawaii and east Asia.
Image of the night sky on November 17 showing the radiance of the Leonid meteor shower – where they appear to be coming from. (Image: Chris Vaughan)
How to watch the Leonids
Watching a meteor shower consists of lying down, looking up at the sky, and waiting. When you sit still, near the ground that cools quickly, you can get very cold. You wait and wait for meteors to appear. When they don’t appear right away, and if you’re cold and uncomfortable, you won’t be looking for meteors for long! So make sure you are warm and comfortable. A comfortable reclining lawn chair, heavy blankets, sleeping bags, pillows and cushions are essential equipment. Hot tea, coffee, or cocoa can ease the chill, as well as provide a light stimulus. It’s even better if you can observe with a partner (“shower with a friend”). That way, you can keep each other awake as well as cover more sky. Because the Leonids move along their orbits around the sun in the opposite direction to Earth’s, they hit our atmosphere almost head-on, resulting in the fastest possible meteor speeds: 45 miles (72 km) per second. Such velocities tend to produce bright and colorful meteors with shades of white, blue, teal and even green, which leave long streaks or trains in their wake. So, for North American observers, the emphasis may be on quality, not quantity. for it would not be surprising if the numbers quoted above by Maslov and Sato fell too far. But some of these meteors, though only visible for a fraction of a second, can leave bright trails of ionized atoms in their wake that hang in the sky for many seconds — or possibly even minutes — as these tiny dust particles make their way through our atmosphere. at altitudes of 80 to 100 miles (130 to 160 km). And seeing even one extremely bright meteor like this can make a cold morning vigil worth it! Joe Rao serves as an instructor and guest lecturer in New York Hayden Planetarium (opens in a new tab). He writes about astronomy for Journal of Natural History (opens in a new tab), the Rural Almanac (opens in new tab) and other publications. Follow us on Twitter @Spacedotcom (opens in a new tab) and then Facebook (opens in a new tab).
