If you like comets, this month is shaping up to be a good season. An assortment of the objects are passing through our cosmic neighborhood, trailed by wisps of gas and dust. This month, skywatchers in the Northern Hemisphere will have the opportunity to observe not one but two once-in-a-lifetime comets in the fall skies.
The celestial visitors, known to scientists as C/2025 A6 (Lemmon) and C/2025 R2 (SWAN), traveled here from the very edges of the solar system where the sun appears as a pinprick of light in the darkness.
A6 (Lemmon) was spotted in January by the Mount Lemmon Survey, which catalogs near-Earth objects from a mountaintop observatory in Arizona.
R2 (SWAN) turned up in early September and is more of an unexpected visitor. It was discovered by Vladimir Bezugly, an amateur astronomer in Ukraine. He found the object in publicly available images from SWAN, or the Solar Wind Anisotropies instrument of the Solar and Heliospheric Observatory, a spacecraft stationed nearly a million miles from Earth.
The comet “caught everybody by surprise,” said Quanzhi Ye, an astronomer at the University of Maryland. That’s because the comet arrived from the direction of the sun, a trajectory that kept the object hidden in the glow of our star during its approach, out of view from sky-scanning telescopes around the world.
What is a comet?
Comets are ancient chunks of ice and rock, leftovers from the creation of the solar system. During an encounter with the sun, a comet gets warmed up. Some ice sublimates into gas, which streams away into space, dragging along dust from the object and producing a shimmery tail.
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The post Two Comets Are Moving Into Your Night Skies in October: How to Watch appeared first on New York Times.
