Interstellar Comet 3I/ATLAS captured speeding through the solar system by Jupiter-bound spacecraft

Interstellar comet 3I/ATLAS captured speeding through the solar system by Jupiter-bound spacecraft

By Jackie Flynn Mogensen edited by Claire Cameron

In late 2025, a mysterious comet flew between the orbits of Earth and Mars and reached a speed of more than 150,000 miles per hour during its closest approach to the sun. Our solar system’s rare interstellar guest has attracted the attention of astronomers, and many have focused their observations on it in an effort to understand what exactly it is, why it is here, and where it might be going.

Each new piece of data offers a glimpse into space beyond our solar system. And as the comet, called 3I/ATLAS, speeds through our cosmic neighborhood, space agencies have co-opted spacecraft to observe it as it goes. The European Space Agency’s Jupiter-bound spacecraft is no exception: A new image of the comet captured last November by the Jupiter Icy Moons Explorer, or JUICE, reveals it to be almost egg-shaped, with a cloud of gas veiling its central core, or core.

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“Although 3I/ATLAS is a visitor to interstellar space, coming from outside the solar system, its behavior is entirely consistent with that expected of a ‘normal’ comet,” the agency said in a statement.

“No one knows where the comet came from,” David Jewitt, director of the Institute for Planets and Exoplanets at the University of California, Los Angeles, said in a statement last year. “You can’t project that accurately to determine where it started on its path.”

Comet 3I/ATLAS has intrigued and excited scientists since its first sighting in July 2025. Its extraordinary speed at the time – 137,000 miles per hour – and strange trajectory indicated that it must have been traveling in interstellar space for perhaps billions of years, according to NASA. Only three interstellar objects have been discovered passing through our solar system. And despite the scramble to observe it as we go, comet 3I/ATLAS remains a mystery.

“It’s like seeing a bullet for a thousandth of a second,” Jewitt said in the same statement.

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