Astronauts aboard the International Space Station (ISS) recently documented a rare celestial event: two bright comets visible alongside vibrant auroras. The images, released by NASA after a period of restricted access due to a government shutdown, showcase the breathtaking beauty of space as seen from orbit.
Rare Double Comet Visibility
Comets Lemmon (C/2025 A6) and SWAN (C/2025 R2) were simultaneously visible in October, a phenomenon that doesn’t occur frequently. Both comets reached peak brightness around October 20th and 21st, offering astronauts a unique opportunity to photograph them against the backdrop of Earth’s atmospheric displays.
Comets are icy bodies that develop spectacular tails as they approach the sun, due to radiation and heat vaporizing their material. These tails, composed of both dust and ionized gas, stretch for millions of miles. Auroras, caused by charged particles from the sun interacting with Earth’s magnetic field, create shimmering light shows in the upper atmosphere.
Astronaut Observations
The ISS Expedition 73 crew captured multiple images of the comets, which NASA later posted to its website and social media. While NASA did not specify which astronauts took the photos, they closely resemble images shared by Japanese astronaut Kimiya Yui of the Japan Aerospace Exploration Agency (JAXA).
Yui was able to continue posting on X (formerly Twitter) during the shutdown, while NASA astronauts were limited to essential duties. He provided detailed descriptions of his observations in Japanese, noting the distinct ion and dust tails visible in the comet Lemmon images.
A Celestial Experience
Yui described one particular image of Comet Lemmon appearing to merge with a stunning aurora display as “like a mermaid swimming through a sea of auroras.” He noted the breathtaking spectacle was so profound that he abandoned his usual informal naming convention for the comet, instead calling it “Lemmon-san” out of respect.
The images reveal Comet SWAN floating above Canada’s Newfoundland and Labrador coastline, with its tail stretching across bands of green and yellow airglow. At the time, Lemmon was 57.2 million miles from Earth, and SWAN was 27.2 million miles away.
The simultaneous visibility of two bright comets is uncommon; their peaks aligning so closely makes this observation even more remarkable. The images captured by the ISS crew serve as a vivid reminder of the dynamic and beautiful universe beyond our planet.
