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The best chance of seeing the strongest meteor shower of the year is on the way this week.
The Geminids, known for their bright, intensely colored meteors, have been streaking the night sky since late November, and the rain will peak on the night of Dec. 13-14, according to the American Meteor Society.
“If you had to pin one (meteor shower) as the best of the year, year after year, it would be the Geminids,” said Robert Lunsford, fireball report coordinator for the company. “Normally, from let’s say the suburban area, in good conditions you could probably see 30-40 meteors (an hour).”
With clear skies and no bright lights in the way, the Geminids can appear at a rate of about 120 visible meteors per hour, according to NASA. However, there’s no escaping the big beacon in the sky that will obscure most of the faintest meteors this year: The moon will shine at 72 percent fullness, according to the American Meteor Society.
“It’s still going to be a good shower, even with the moon out,” said Bill Cooke, head of NASA’s Meteoroid Environment Office. “Find a suitably dark sky, find something that will block the moon, maybe a building or a tree, and watch the sky away from the moon.”
First observed in the mid-1800s, the shower initially delivered no more than 20 visible meteors per hour. Since then, the Geminids have reappeared every year, in increasing numbers. By the 1960s, the event had overtaken the major August Perseids, once the heaviest rainfall with hourly rates of 50 to 100 meteors.
It’s unclear how the Geminids might change in the foreseeable future, Cooke said, with some models indicating the shower will increase in intensity and others estimating a gradual decline over the next few decades.
The Geminids are unique in that their source is asteroid 3200 Phaethon, while most other meteor showers are born from icy comet debris. That’s why Geminid streams can be unpredictable — because asteroid breakups are more difficult to model, Cooke said.
Asteroid 3200 Phaethon is unusual in itself, behaving like a comet as it approaches the sun. It also has an orbit, which it completes about every 1.4 years, that is closer to the sun than any other asteroid. When 3200 Phaethon is near Earth, the asteroid sheds its dusty debris, hence the display of the Geminids.
The Geminids are active from Nov. 19 to Dec. 24, according to EarthSky, but their hourly rates don’t start to hit the double digits until Dec. 10, Lunsford said.
The shower is known to be friendly to families and young viewers in North America, as it is the single large shower that sees the most activity before midnight. The meteors appear to radiate from the constellation Gemini, which will rise into the sky around 10 p.m. ET, Lunsford said.
“You can watch when the radiant is at its peak, which is between 1 a.m. and 2 a.m. EST with moonlight, or you can try watching earlier in the evening when the moon is still below the horizon,” Lunsford said. “Rates will likely be quite similar at those times as well.”
The Geminids will be visible from all parts of the world, but for the Southern Hemisphere it is best to see around the middle of the night at 2am local time, as the radiant will need to be at its peak to be seen. The position of the radiant will be low on the horizon and will also cause meteors to appear at a reduced rate, Lunsford said.
According to NASA meteor camera data, the Geminid shower is among the best for producing fireballs, meteors brighter than the planet Venus, second only to the Perseids, Cooke said. The largest and brightest Geminid meteors are often said to appear greenish in color.
Moon illumination has affected Geminid viewing for the past two years, but the meteor shower is expected to occur around a new moon in 2023, creating perfect viewing conditions.
“When you see a meteor burning in Earth’s atmosphere, you’re seeing something that’s been in space for a very long time,” Cooke said. “From a scientific point of view, by studying it, we can learn something about what makes up these comets. To the casual observer, they are a beautiful fireworks display (meteor showers are the nature fireworks.
The next and last major annual meteor shower of 2022 will be the Ursids, which will peak on the evening of December 22, according to EarthSky.