Subj : Daily APOD Report To : All From : Alan Ianson Date : Mon Dec 01 2025 00:44:00 Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2025 December 1 A starfield is shown around a comet. The green coma of the comet is on the lower left. A meandering blue-tinted tail goes off to the upper right. A slight anti-tail is seen from the coma toward the lower left. Please see the explanation for more detailed information. 3I ATLAS: Tails of an Interstellar Comet Image 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. Explore the Universe: Random APOD Generator Tomorrow's picture: active galaxy __________________________________________________________________ Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP) NASA Official: Amber Straughn Specific rights apply. NASA Web Privacy, Accessibility, Notices; A service of: ASD at NASA / GSFC, NASA Science Activation & Michigan Tech. U. --- BBBS/Li6 v4.10 Toy-7 * Origin: The Rusty MailBox - Penticton, BC Canada (1:153/757) .