Meteor showers are the occasional reminder that the solar system is full of dirty and icy clumps, but you wouldn't describe them that way when you see them shining across the night sky.
These light shows in Earth's celestial canopy show off just how dynamic and active our universe really is, with their dazzling flashes appearing faster than any other object in the night sky, like the movement of constellations or the passing shadow of a lunar eclipse.
This year's best meteor shower will probably be the summertime Perseids, but there are also other meteor showers with promising shows. There's also a new shower that will appear in Earth's atmosphere in 2021.
Bill Cooke, the lead for the Meteoroid Environment Office at NASA's Marshall Space Flight Center in Huntsville, Alabama, spoke with Space.com and offered skywatching tips and details on the major meteor showers visible this year.
Meteor showers are an investment of time and preparation is key to seeing them, according to Cooke, but it's worthwhile because it's cheap — no telescope or binoculars are necessary — and the simplest form of astronomy there is.
Meteor shower observing can't be done on a whim, but it's pretty straightforward: Get away from bright lights, take time to adjust your eyes to the dark night sky and avoid looking at your cellphone if you get bored. The bright screen can throw a wrench in your efforts to adjust your night vision. "My suggestion to my friends who want to observe meteors is, leave your phone inside," said Cooke.
Give your eyes 30-45 minutes to adapt to the dark, he said, and take in as much of the sky as possible by lying down flat on your back. Meteors can appear anywhere in the sky, and the more sky you see, the better your chance is to spot one.
Each shower has a radiant, or a point in the sky where the meteors appear to originate. Knowing where the radiant is can be helpful, though the longer streaks will be visible farther away from the radiant. "You do not want to look at the radiant," Cooke said. "A good philosophy is to lie on your back and look straight up. And that way, you take in as much of the sky as you can."
Keep in mind that some sky conditions can impede successful viewing of shooting stars. Cloud coverage could block the sky, and the moon could also tarnish meteor shower viewing even on a clear night. Depending on the lunar phase, the amount of moonlight will wash out the faint meteors.
Sometimes meteor showers produce streaks that are exceptionally bright. Observers can occasionally spot fireballs, or meteors brighter than Venus, the brightest planet in the night sky. The rate of shooting stars can be higher than usual in some instances, too, when the stream of space rocks gets a gravitational "nudge" from the planet Jupiter.
Meteor showers happen when Earth passes through the debris field of a comet or asteroid as these objects make their way around the sun, shedding "crumbs" along the way. That's why a given meteor shower generally appears around the same time each calendar year. And occasionally, when Jupiter gets close to a stream of debris, its immense gravity perturbs the particles, nudging them slightly closer to Earth and thereby increasing the amount of meteors visible in the night sky. Occasionally, this can produce outbursts, or brief periods of intense activity in which skywatchers can see more than 1,000 meteors per hour.
Most annual meteor showers don't outburst, though, and are typically classified as strong, medium or weak showers, depending on their peak rates. This guide will feature strong and medium showers occurring in 2021, when observers have a good chance to spot a meteor streak.
Lyrid meteor shower — peaks April 21-22
The Lyrid meteor shower is a medium-strength shower, according to the American Meteor Society (AMS). It will peak on the night of April 21 into the morning of April 22, displaying about 18 meteors per hour in a clear sky. The moon will be 68% full, so the moonlight may interfere with your observations. The radiant of the Lyrids will be high in the northern hemisphere's sky during the near-dawn hours.
Viewing conditions won't be the best this year for the Lyrids, Cooke said, but there's an early-morning window of time when observers can get a good shot of seeing these meteors.
Where to see the Lyrids
The radiant will be between the constellations Lyra and Hercules. The bright star Vega is part of Lyra, so you can also look for it to get a good idea of where the radiant for the Lyrids will be.
Viewers should have a good view of the meteor shower for the three days around the shower's peak, according to AMS. "Get up early before dawn, after the moon has set. You have a pretty good chance of seeing some Lyrids this year," said Cooke.
Astronomers think the source for all the space bits that create the Lyrid meteor shower is Comet Thatcher. The Lyrids have been viewed by different cultures for the past 2,700 years, according to NASA.
Eta Aquarid Meteor shower — peaks May 4-5
In the predawn hours of May 6, observers get the chance to spot the Eta Aquarids at their peak. The maximum rate for shooting stars in a perfectly clear sky will be about 40 to 50 per hour, according to Cooke. These fast meteors travel across the sky at about 42 miles (67 kilometers) per second, according to AMS.
The moon will be in its waning crescent phase (about 38% full) when the shower peaks. The moon will then progressively get dimmer in the days following the peak, so the few days after May 6 may offer the best lunar conditions for the Eta Aquarids.
These chunks of space debris come from a celestial icon: Halley's Comet. The Eta Aquarid meteor shower is categorized as a strong shower and is best viewed from the Southern Hemisphere or close to the equator. Folks in some northern latitudes, however, can also observe them.
Where to see the Eta Aquarids
People close to the equator will have the best chance to see the Eta Aquarids. The meteors radiate from the constellation Aquarius, which dwells in the southern sky. This means that the radiant for these shooting stars will be lower on the horizon for those viewing from the Northern Hemisphere, and it will appear higher in the sky for observers in the Southern Hemisphere.
"The Etas are not a shower that you can go out to see after sunset, because the radiant won't be up," said Cooke. To see the Eta Aquarids, Cooke recommends getting up to be outside at 2:00 a.m. local time. From then on, the rates will continue to increase until dawn.
These meteors are short, swift streaks, produce long trains, according to AMS, and travel at about 41 miles (66 km) per second.
Perseid meteor shower — peaks August 11-12
The Perseids are a strong meteor shower that produce rich and bright streaks. Cooke said that 2021 will be a great year to catch them.
Viewers can start observing around 11 p.m. local time, when the rates of shooting starts increasing, and can watch the sky until dawn. "The good news is there will only be a crescent moon which will set early in the night, so you will have no interference from moonlight," Cooke said.
Where to see the Perseids
If there's a clear sky, the Perseids will have a meteor rate of about 100 visible "shooting stars" per hour.
In more typical viewing conditions when the radiant isn't at its highest point in the sky or if there is some cloud coverage, people will see one Perseid per minute, Cooke said. "The Perseids are rich in fireballs, so they'll be bright," he added.
'Finlay-id' meteor shower — peak in October 2021
"On Oct. 5 of this year, for the first time, Earth will encounter particles from Comet Finlay," he said. The shower doesn't yet have an official name, according to Cooke, but that it does have a nickname at NASA. "We've been calling them the 'Finlay-ids' after the comet."
Where to see the 'Finlay-ids'
The faint shower will only be visible from the southern parts of the Southern Hemisphere, but NASA researchers will be observing the event, he said. They'll be faint because a meteor's brightness depends on its size and how fast it is moving. In the case of the Finlay-ids, they will only be moving at about 9 miles (15 km) per second, Cooke said.
These particles from Comet Finlay were ejected from the icy object in 2008, Cooke said. Although most of the world may not see these shooting stars, the Finlay-ids are certainly a reminder about just how dynamic the solar system can be.
Orionid meteor shower — peaks October 20-21
Like the Eta Aquarids, the Orionid meteor shower is a by-product of Halley's Comet. In 2021 the Orionids will peak on the night of Oct. 20, with clear-sky rates of about 20 meteors per hour. However, the moon may interfere with observations this year.
The moon will be full on Oct. 20 and its light will "wash out the Orionids," said Cooke.
"The Orionids are going to, frankly, suck this year ... the moon will be up all night, from sunset to sunrise."
Where to see the Orionids
Orionids are named for their radiant near the constellation Orion, the hunter, which is one of the easier constellations to spot with the three stars that make up it's "belt."
The period of activity peaks on Oct. 20 but begins on Oct. 2nd and lasts until Nov. 7th. For Orionid viewing, it's best to go outside on nights closer to the bookends of this shower, when the moon isn't as full or when it has set. The meteors may not be appearing as frequently as they would in late October, but there will be less moonlight to interfere with observations in early October and early November.
Leonid meteor shower — peaks November 16-17
The Leonids offer clear-sky meteor rates of about 10 to 15 shooting stars per hour.
Like the Orionids, this year's Leonids will also peak during bad moon conditions. According to AMS, the moon will be 95% full on the night of Nov. 16.
"Don't expect much out of the Leonids this year," Cooke said.
Where to see the Leonids
The Leonids' radiant is located in the sickle-shaped head of the constellation Leo, the lion.
Leonid skygazing can be incredible, or it can be dull. It all depends on where its parent body, Comet 55P/Tempel-Tuttle, will be in its orbit and the kind of debris clumps that will be around when our planet passes through this comet's orbit.
The Leonids put on big shows in 1966, 1999 and 2001, according to AMS, when the comet was making its closest approach to the sun. It will be several years until observers get a big show from the Leonids.
"The best we can hope for now until the year 2030 is peaks of around 15 shower [meteors] per hour and perhaps an occasional weak outburst when the earth passes near a debris trail. The Leonids are often bright meteors with a high percentage of persistent trains," according to AMS.
Geminid meteor shower — peaks December 13-14
The Geminid meteor shower in December can produce 130 to 140 meteors per hour on a clear sky, said Cooke.
Though it's a chilly time in the Northern Hemisphere, the Geminids will peak on the night of Dec. 13, when AMS says the moon will be 78% full.
Year after year, the Geminids are the strongest meteor shower in terms of rates. Cooke previously said that when the shower was observed in the 1830s, rates were about 30 meteors per hour, and now, well over 100 appear per hour.
Unlike the other showers on this list, the Geminids are the by-product of an asteroid. The debris that falls onto Earth's atmosphere during this meteor shower comes from asteroid Phaethon.
Where to see the Geminids
The meteor shower's radiant is located in the constellation Gemini, which rises around sunset. The shower is best viewed from the Northern Hemisphere but can be viewed from the Southern Hemisphere, although at a reduced meteor rate.
The moonlight conditions in 2021 mean that observations will be the best after moonset at about 2:00 a.m. local time, said Cooke. Viewers can then enjoy the Geminids until dawn.
Geminid meteors are bright and "intensely colored," according to AMS, although they aren't likely to produce long trails. These meteors are also visible in the southern hemisphere, but at reduced rates.
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