NASA Mars Rover Captures Rare Images of Interstellar Comet 3I/ATLAS Passing Mars

The interstellar object 3I/ATLAS, believed to be a large comet up to seven miles wide traveling at around 130,000 mph, made its closest approach to Mars on October 3, 2025. NASA's Perseverance rover captured images of 3I/ATLAS using its Right Navigation Camera, showing an elongated streak in the Martian sky. Harvard astronomer Avi Loeb explained that this stripe, about 50,000 kilometers long, is an artifact caused by the long integration time of the camera as the object moved across the sky, rather than the actual size or shape of the comet. Observations from multiple telescopes and space missions, including Hubble, James Webb, and SPHEREx, confirm that 3I/ATLAS is much smaller, with an upper diameter bound of around 46 kilometers. Despite some online speculation about the object resembling a cylindrical spacecraft, scientific analysis supports that the images represent a blurred view of the comet due to the camera's exposure settings and the object's high velocity. This event provides a rare opportunity for astronomers to study one of only three known interstellar objects visiting the solar system.