Comet 3I/ATLAS is the largest, fastest-moving, oldest object ever seen: Can probes catch the tail of Manhattan-sized space visitor?

The interstellar comet 3I/ATLAS, believed to have originated from outside our solar system, was first detected in July 2025 by the ATLAS survey telescope and has sparked curiosity among scientists. Some conspiracy theories suggest that the comet is an alien spacecraft, while others have been well-thought out suggestions, like using Martian-based probes to observe the comet as it streaked past the red planet.

Two space probes racing through the solar system could soon make history by flying through the tail of a mysterious, Manhattan-sized comet hurtling toward Earth. However, this is only possible if scientists act quickly to adjust their trajectories.

Hera and Europa Clipper are now ideally positioned to intercept the debris trail of comet 3I/ATLAS, according to a new study published in the Research Notes of the American Astronomical Society. As 3I/ATLAS streaks through the solar system over the coming weeks, it will leave a trail of particles in its wake. Both probes are set to pass “downwind” of the comet, offering researchers a rare—and potentially unprecedented—chance to fly directly through a comet’s tail, Live Science reports.


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Probes to catch tail of 3I/ATLAS?

Though the probes won’t pass directly through the comet’s tail. Instead, they will traverse a surrounding field where the comet’s particles are being carried into space by the Sun’s solar wind. Although this dispersal field lies roughly 5 million miles from the comet, it remains close enough for the probes to gather crucial data from the particles the comet sheds.

Hera and Europa Clipper could be science’s best bet to gather information from the object. But they will only be in that position over the next two weeks, and scientists would need to act immediately to send them on course to meet the comet’s tail, according to Live Science.

Hera might not be of much help either — the probe is currently en route to study an asteroid and lacks the instruments needed to analyze particles from 3I/ATLAS. However, NASA’s Europa Clipper, now on its way to investigate the icy surface of Jupiter’s moon Europa, is equipped with precisely the kind of instruments suited for that task.

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Comet 3I/ATLAS largest, fastest moving object ever seen

Live Science reports that the interstellar comet 3I/ATLAS is the largest, fastest-moving, and quite likely the oldest interstellar object ever seen. The rare visitor is nearing the halfway point on its tour of our solar system. This Wednesday (Oct. 29), 3I/ATLAS will reach perihelion — its closest point to the sun — before beginning its months-long departure from our cosmic neighborhood.

As 3I/ATLAS reaches perihelion this week — coming within 1.4 astronomical units, or 130 million miles (210 million kilometers) of the sun, according to NASA — it may start releasing gas in overdrive. When the comet becomes visible to telescopes again in early November, it may look both bigger and brighter than how it appeared two months ago.

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3I/ATLAS has left scientists puzzled since it was first spotted in June. Though few have disputed that it is anything but a comet, its irregular and unusual behavior and make-up have some like Harvard astrophysicist Avi Loeb speculating it could be an intelligently-operated alien probe.

When it will fly close to Earth, the interstellar comet 3I/ATLAS will be hidden behind the sun and impossible for Earthen telescopes and cameras to get a good look at it. The object is also ejecting a nickel alloy only ever found in human manufacturing, and previously emitted an “anti-tail” from its front that Loeb speculated could be some kind of “braking thrust” system.