A Rare Interstellar Comet Just Flew by Mars—Here Are the Photos Captured by an Orbiting Spacecraft

The images offer the closest view yet of comet 3I/ATLAS, famous for being only the third known interstellar object to pass through our solar system

Sara Hashemi | Daily Correspondent

October 9, 2025

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3I/ATLAS, the rare comet currently making headlines as it travels through our solar system, made its closest approach to Mars on Friday. Thanks to the European Space Agency’s (ESA) ExoMars Trace Gas Orbiter, we can see the closest view yet of this interstellar visitor.

ESA released the images October 7, combining them into a short animation of the comet as it traveled about 19 million miles away from the orbiting spacecraft.

The images are impressive, coming from a camera that “is designed to observe Mars,” Nicolas Thomas, an experimental physicist at the University of Bern in Switzerland and the principal investigator for the camera, tells Kenneth Chang at the New York Times.

They show a bright dot—the comet’s nucleus of ice and dust—and a coma, the nebulous atmosphere of dust and gas surrounding the comet’s nucleus. The coma is produced by the heat and radiation from the sun, which in turn lead the comet to release gas and dust, creating its signature glow.

Astronomers haven’t been able to spot the comet’s tail in the new images, but it might appear as the comet continues to heat up, releasing more ice as it hurtles through space.

“This was a very challenging observation for the instrument. The comet is around 10,000 to 100,000 times fainter than our usual target,” adds Thomas in a statement.

3I/ATLAS is only the third known interstellar object to move through our solar system, providing a key opportunity for astronomers to learn about conditions of the more distant cosmos. Colin Wilson, a project scientist for the Trace Gas Orbiter, tells the New York Times that the images alone don’t reveal any new information about the comet. However, he says, they will help scientists better understand how an interstellar comet like 3I/ATLAS might differ from one that originates in our own cosmic neighborhood.

NASA’s Mars Reconnaissance Orbiter has also captured images of the comet, but most of the agency is currently closed due to the ongoing government shutdown in the United States. Wilson tells the New York Times that the data is seemingly “quite good”—a sign of even more to come during Earth’s brief date with 3I/ATLAS.

Another ESA spacecraft, Mars Express, did not appear to capture the comet in its images, because its camera uses a shorter exposure time than the one on the Trace Gas Orbiter. Scientists will continue to analyze those images to see if they can spot it, according to the statement.

Researchers hope the data will eventually reveal more about our cosmic guest—and offer a valuable glimpse at an object that originated in another star system. “These objects are the first building blocks we can observe from those systems,” explains Michael Küeppers, a project scientist on ESA’s Comet Interceptor mission, to Ian Sample at the Guardian. “They tell us about the conditions in the stellar system where they formed.”

The comet is expected to reach its closest point to the sun around the end of October. After that, ESA’s Jupiter Icy Moons Explorer will observe the object. That data will not be available until February 2026, according to ESA. But it may be worth the wait: The upcoming observations are expected to show the comet at the peak of its activity, since they’ll take place after its impending brush with the sun.

In March 2026, the comet will pass Jupiter. Then, it’ll leave our solar system forever.

Sara Hashemi | Read More

Sara Hashemi is a science writer and fact-checker currently based in New York City. Her work has appeared in Sierra, The Body, Maisonneuve magazine and more.