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.

2024 October 21
A starfield is shown with a bright comet. The main
tail of the comet points diagonally to the upper left, while
a thin anti-tail points to the lower right. Mountain peaks
are visible at the bottom in the foreground. 
Please see the explanation for more detailed information.

Comet Tsuchinshan-ATLAS over California
Credit & Copyright: Brian Fulda

Explanation: The tails of Comet Tsuchinshan-ATLAS were a sight to behold. Pictured, C/2023 A3 (Tsuchinshan–ATLAS) was captured near peak impressiveness last week over the Eastern Sierra Mountains in California, USA. The comet not only showed a bright tail, but a distinct anti-tail pointing in nearly the opposite direction. The globular star cluster M5 can be seen on the right, far in the distance. As it approached, it was unclear if this crumbling iceberg would disintegrate completely as it warmed in the bright sunlight. In reality, the comet survived to become brighter than any star in the night (magnitude -4.9), but unfortunately was then so nearly in front of the Sun that it was hard for many casual observers to locate. Whether Comet Tsuchinshan-Atlas becomes known as the Great Comet of 2024 now depends, in part, on how impressive incoming comet C/2024 S1 (ATLAS) becomes over the next two weeks.

Your Sky Surprise: What picture did APOD feature on your birthday? (post 1995)
Tomorrow's picture: star pillars


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