Planet Mercury's Comet-like Tail (sodium spectrum-view)

Planet Mercury's Comet-like Tail (sodium spectrum-view)

Astrophotographer Steven Bellavia: "A 24 million km long plume of gas is ejected from Mercury's thin atmosphere due to the sun, very much like a comet. This is only visible using a narrowband filter that captures the bright yellow sodium light at 589nm. A tail was predicted in the 1980s, and first discovered in 2001. Multiple observations by NASA's robotic MESSENGER spacecraft that orbited Mercury between 2011 and 2015 revealed more details of this tail."

Mercury is the first planet from the Sun and the smallest in the Solar System. It is a rocky planet with a trace atmosphere and a surface gravity slightly higher than that of Mars. The surface of Mercury is similar to Earth's Moon, being heavily cratered, with an expansive rupes system generated from thrust faults, and bright ray systems, formed by ejecta.

Learn more about investigations of Mercury's tail by NASA's MESSENGER spacecraft:
https://science.nasa.gov/photojournal/exploring-mercurys-tail/

https://science.nasa.gov/mercury/

Image Credit 1: Steven Bellavia

Image Credit 2: Canadian Space Agency (CSA)

Steven's website: https://www.astrobin.com/users/bellavia/collections/
Location: Surry, Virginia
Image Date: Dec. 3, 2025

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