NEW YORK – Sky enthusiasts in the Northern Hemisphere are currently treated to a captivating celestial event, as two vivid green comets streak across the night sky.

These comets, originating from the distant reaches of our solar system, possibly the Oort Cloud beyond Pluto, are making their presence known. Comet Lemmon is expected to make its closest approach to Earth around Tuesday. Meanwhile, Comet SWAN is anticipated to pass by Earth on Monday, although it is moving away from the sun and might become less visible over time.

Witnessing two comets at once without the aid of telescopes is “rare, but not unprecedented,” according to Carson Fuls, who directs the University of Arizona sky survey responsible for discovering Comet Lemmon.

For those eager to catch a glimpse, head outside just after sunset. Look to the northern horizon to spot Comet Lemmon, while Comet SWAN will be visible towards the southwest, also near the horizon.

Binoculars should suffice to view these celestial visitors until the end of the month, though their future brightness remains uncertain, notes Valerie Rapson, an astronomer at the State University of New York at Oneonta.

Comets are frozen leftovers from the solar system’s formation billions of years ago. They heat up as they swing toward the sun, releasing their characteristic streaming tails.

Comet Lemmon, also designated C/2025 A6, was discovered in January by a telescope scouring the night sky for near-Earth asteroids. Comet SWAN, also known as C/2025 R2, was spotted in September by an amateur astronomer using photos from a spacecraft operated by NASA and the European Space Agency.

The comets are green because of gases streaming off their surfaces. From Earth, they’ll look like gray, fuzzy patches.

Earlier this year, a green comet broke up as it swung by the sun, dashing hopes of a naked-eye spectacle. A bright comet called Tsuchinshan-Atlas zoomed by Earth in 2024, and other notable flybys included Neowise in 2020 and Hale-Bopp and Hyakutake in the 1990s.

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