This year, the night sky is putting on a show with the Orionid meteor shower, a new moon and two green comets filling the night sky.
Each October, Earth drifts through the dusty trail left behind by Halley’s comet, creating the annual Orionid meteor shower.
When and where to watch
This year, peak viewing times are expected early in the mornings of Oct. 21-23, between 1 a.m. and dawn, according to the American Meteor Society. Even outside of these hours, meteors will still be visible in the night sky.
The best conditions to see the most meteors is under dark, rural skies, where viewers could see up to 20 meteors per hour. Thanks to the new moon on Oct. 21, this year offers some of the best Orionid viewing conditions possible, unless, of course, clouds or city lights interfere, the American Meteor Society notes.
Plus, 2 comets at once?
If the Orionids weren’t enough, two comets — known as C/2025 A6, (Lemmon) and C/2025 R2 (SWAN) — will reach their closest approach to Earth.
Astronomer Gianluca Masi will host a special livestream on Oct. 20 beginning at 11:30 a.m. MDT to watch as both comets pass Earth.
“So far, living in the Northern hemisphere, I could admire C/2025 A6 Lemmon only,but C/2025 R2 SWAN is quickly joining the show,” Masi told Space.com. “We are ready to amaze every astronomy lover with our live feed!”
How rare is this?
Seeing two visible comets at once is what Space.com calls a “rare cosmic treat.”
Comet Lemmon will come within 56 million miles of Earth and Comet Swan will pass even closer, at about 24 million miles away.
Both comets will reach peak brightness between Oct. 20-21 and should remain visible through early November, gradually fading as they move away from Earth’s surface.
Comet Lemmon — discovered in January — will be easiest to spot in the western sky after sunset using binoculars or a small telescope.
SWAN, discovered in September, is best viewed just before dawn.
Isn’t there another Comet Lemmon? Yes, in fact there are about 70 of them, named for the observatory that detected them, Carson Fuls, director of the Catalina Sky Survey, told National Geographic.
“Comets are very common,” Rhonda Stroud, the director of the Center for Meteorite Studies at Arizona State University in Tempe, Arizona, told National Geographic, “but Comet Lemmon is definitely the best comet to view from Earth this year.”
Why the green glow?
The green glow comes from diatomic carbon (C2), a molecule that, when broken down by solar radiation, emits a green light, National Geographic details.
Typical comets are made up of carbon monoxide, carbon dioxide and water ice, but the ratio of each element gives comets their unique hue.
“Every comet that we have imaged up close with a spacecraft looks different from the others,” says Stroud.