A mysterious explosion from a visitor from another star system

Space · Published 23 October 2026 Swipe more like this →

In short: 3I/ATLAS is leaving our solar system forever, but it left behind a scientific puzzle. This interstellar comet recently underwent a mysterious explosion that has left astronomers scrambling to understand its behavior before it recedes into the deep void of space.

3I/ATLAS is the third known interstellar object discovered passing through our celestial neighborhood. It was first reported by the ATLAS survey telescope in Chile on July 1, 2025, though archival data from three other ATLAS telescopes and Caltech’s Zwicky Transient Facility suggests it was visible as early as June 14, 2025. Astronomers confirmed its interstellar origin by tracing its hyperbolic orbital path, which does not form a closed loop around our Sun. The naming convention identifies the ATLAS survey team as the discoverers. The prefix 'I' specifically denotes its status as an interstellar traveler. Because it is the third such object found, it carries the number 3 in its designation.

The comet's journey through our system was marked by several key milestones. On 30 October 2025, the object neared the Sun most closely, measuring roughly 1.4 au (130 million miles) away. It remained far from Earth, maintaining a minimum distance of about 1.8 astronomical units (170 million miles). After passing too close to the Sun for ground-based observation in September 2025, it reappeared on the opposite side in early December 2025. The comet's closest approach to our planet occurred at a distance of approximately 270 million kilometers. It moved through the solar system without posing any threat to Earth. Its path was tracked by various international teams of astronomers.

The object's behavior has sparked significant interest, particularly a mysterious explosion that may alter current scientific understanding of interstellar bodies. While NASA's Hubble Space Telescope helped estimate its size, its physical properties remain under investigation. As it moves past Jupiter and into deep space, researchers are racing to capture final images and data from this rare visitor before it is lost to the cosmos forever. Two orbiters and a rover from NASA captured images of the comet from the nearest possible locations. These images were used to study its physical properties. Scientists are now making final observations before the object recedes into deep space.

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