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APOD: 2025 December 1 Á 3I ATLAS: Tails of an Interstellar Comet
<< Yesterday 30.11.2025
APOD: 2025 December 1 Á 3I ATLAS: Tails of an Interstellar Comet
Credit & Copyright: Victor Sabet & Julien De Winter
Explanation: How typical is our Solar System? Studying 3I/ATLAS, a comet just passing through, is providing clues. Confirmed previous interstellar visitors include an asteroid, a comet, a meteor, and a gas wind dominated by hydrogen and helium. Comet 3I/ATLAS appears relatively normal when compared to Solar System comets, therefore providing more evidence that our Solar System is a somewhat typical star system. For example, Comet 3I/ATLAS has a broadly similar chemical composition and ejected dust. The featured image was captured last week from Texas and shows a green coma, a wandering blue-tinted ion tail likely deflected by our Sun's wind, and a slight anti-tail, all typical cometary attributes. The comet, visible with a telescope, passed its closest to the Sun in late October and will pass its closest to the Earth in mid-December, after which it will return to interstellar space and never return.

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
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Based on Astronomy Picture Of the Day