- The Orionids meteor shower peaks late Wednesday night and into early Thursday morning.
- Up to 20 shooting stars per hour will streak across the sky, but a full moon will make it hard to see them.
- The Orionids happen annually when Earth travels through debris left by Halley's Comet.
NASA calls the annual Orionids meteor shower one of the most beautiful of the year, due to the many speedy meteors that move across the night sky.
The meteors streak into Earth's atmosphere at speeds of 148,000 miles per hour, which prompts them to leave glowing trails that can linger for several seconds, if not minutes. Some become fireballs that explode with light and color.
The 2021 Orionids shower peaks Wednesday evening and early Thursday morning. Sky watchers can expect to see between 10 and 20 shooting stars per hour at those times.
However, the peak of this year's shower will be overshadowed by the light of a full moon, known as the Hunter's Moon because it falls in October. That likely means the Orionids will be underwhelming for most viewers.
"The Orionids are going to, frankly, suck this year," NASA meteor expert Bill Cooke told Space.com. "The moon will be up all night, from sunset to sunrise."
Traveling through the dust of Halley's Comet
The Orionids happen when Earth's orbit takes it through a lane of space debris left behind by Halley's comet. As sand-grain-sized fragments of the comet - known as meteors - strike our atmosphere, they burn up, leaving fiery streaks in the sky.
Earth passes through Halley's wake twice a year, once starting in May and then again in October. Each pass lasts a month or so, which is why the resulting meteor showers - the Eta Aquariids in the spring, and Orionids in the fall - last for weeks. The American Meteor Society predicts the Orionids will last through November 7.
Each shower's peak, though, occurs when our planet moves through the densest part of Halley's debris trail.
No need for binoculars, and don't stare at Orion
To maximize your chance of seeing the Orionids, find a dark spot as far from light sources as possible. If you're in the Northern Hemisphere, lie on the ground and gaze toward the southeast.
You can see the shower starting after midnight local time on Thursday.
The Orionids are easily visible with the naked eye, but it's best to let your eyes adjust to the darkness for 30 minutes before attempting to spot shooting stars. Avoid looking at the moon or your phone as well, since bright light may stymie your efforts to spot faint meteors.
NASA recommends against using telescopes or binoculars to view a meteor shower, since those instruments show only a limited portion of the sky at a time.
The Orionids shower gets its name from the Orion constellation, which is where the meteors seem to originate in the sky - they appear north of Betelgeuse, the constellation's brightest star. Orion is identifiable by the trio of stars forming a hunter's belt. But NASA suggests not staring directly at Orion, as doing so will make meteors appear dimmer.
If you don't spot any meteors during this year's shower, mark your calendar for mid-November, when the Northern Taurids shower is expected to peak.