ESA’s ExoMars Trace Gas Orbiter captured rare close-up images of comet 3I/ATLAS passing Mars at 130,000 mph — the faint interstellar visitor showed a gas coma but no tail.
ESA’s ExoMars Orbiter captures closest images of comet 3I/ATLAS near Mars, showing a faint coma, no tail
Photo Credit: ESA
In early October 2025, ESA's ExoMars Trace Gas Orbiter snapped the closest-ever images of the interstellar comet 3I/ATLAS as it flew past Mars. In the photos, several fuzzy bright comas of gas around the icy core of the comet can be seen; however, no tail can be seen at all as yet. On October 3, the comet flew 30 million km (18.6 million miles) around Mars, with it travelling at approximately 130,000 mph.
According to ESA, Mars orbiters turned their cameras to the comet on the 3rd of October. ExoMars TGO recorded numerous 5-second exposures at a distance of approximately 30 million km using the camera (CaSSIS), which was afterwards assembled into an animation. The comet is a small fuzzy white spot - the icy nucleus of the comet enclosed in one cloud of gas (coma). The 3I/ATLAS lead investigator, Nick Thomas, indicated that the target of 3I/ATLAS is 10,000 to 100,000 times weaker than conventional targets, which is why a tail does not appear in the images. The Mars Express satellite, which was also older, attempted to shoot it, though its short 0.5-second exposures were unable to resolve the comet.
The third certain interstellar object in our solar system and perhaps the largest, is Comet 3I/ATLAS, which is 511 km in diameter. It has swept over the galaxy over billions of years, probably the oldest comet seen, possibly several billion years older than the Solar System. Having been closest to the Sun on October 30, 3I/ATLAS will come near Jupiter at the beginning of 2026 and then leave the solar system.
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