APOD: 2025 December 1 – 3I ATLAS: Tails of an Interstellar Comet
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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
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.
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Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell (UMCP)
NASA Official: Amber Straughn
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