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 January 26
A dark sloping hill is seen at the bottom with a 
bright comet with many tails visible above it, taking
up most of the frame. The tails closest to the slope 
are the most dim. 
Please see the explanation for more detailed information.

The Many Tails of Comet G3 ATLAS
Image Credit & Copyright: Martin Mašek (FZU, Czech Academy of Sciences) & Jakub Kuřák

Explanation: Why does this comet have so many tails? C/2024 G3 (ATLAS) has developed several long and intricate tails visible from Earth's southern hemisphere over the past two weeks. Many observers reported seeing the impressive comet without any optical aid above the western horizon just after sunset. At least six different tails appear in the featured image captured five days ago from the dark skies above Paranal Observatory in Chile. One possible cause for the multiple tails is dust and gas being expelled from the comet's rotating nucleus. The outward push of the Sun's complex solar wind may also play a role. The huge iceberg-like nucleus of Comet ATLAS appears to have broken up near its closest approach to the Sun two weeks ago. Unfortunately, Comet ATLAS and its tails are expected to fade significantly over the coming weeks.

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


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