NASA’s Hubble Space Telescope has made an exciting discovery: a comet breaking apart in real time. The comet, named C/2025 K1 (ATLAS), was spotted unexpectedly during Hubble’s routine observations of space. Scientists were surprised to see its nucleus actively disintegrating.
John Noonan, a physics professor at Auburn University and co-author of the study, noted, “Sometimes the best science happens by accident. We had to find a new target to observe, and right when we did, the comet started to break apart.” This kind of event is incredibly rare, emphasizing just how fortunate this observation was.
Comets like K1 are often called “dirty snowballs” because they are made of ice, dust, and rocky materials. When they approach the sun, they heat up, releasing gas and dust that create striking comas and tails. Unfortunately, this heat can also lead to disintegration when the forces become too much for the comet to bear.
Hubble observed K1 over three days, from November 8 to November 10, 2025. By then, the comet had already started breaking into at least four fragments, and one piece seemed to split again during the observations. Researchers estimate that this breakup likely began a week earlier, coinciding with K1’s closest approach to the sun—a point known as perihelion, when temperatures and stress on the comet are highest.
K1, discovered by the ATLAS survey in May 2025, hails from the Oort Cloud, a distant region filled with icy bodies. Comets like K1 serve as time capsules from the early solar system, holding material unchanged for billions of years. Before its fragmentation, K1 measured about 5 miles (8 kilometers) across, larger than the average comet.
Interestingly, ground-based observers did not see K1 brighten immediately after its breakup. Instead, there was a delay, which puzzled researchers. They believe that the brightness of a comet primarily comes from sunlight reflecting off dust rather than ice. It’s possible that newly exposed ice requires time to form a dust layer or to build heat beneath its surface before it can release a cloud of dust.
Noonan noted, “This is a significant moment for scientists. Hubble caught a fragmenting comet closer to its disintegration than ever before.” This direct observation allows researchers to learn valuable insights about what happens at a comet’s surface during such events. It reveals the timeline needed to build dust that can be expelled by gas, helping us understand the life cycles of these ancient solar system objects.
Real-time observations of a comet breaking apart are incredibly rare. The unpredictable nature of these events makes them difficult to study. Hubble’s high-resolution images provided scientists with a clear view of K1’s disintegration, allowing them to track the fragments as they drifted apart. This rare glimpse offers a valuable opportunity to understand the evolution of some of our solar system’s oldest inhabitants.
The findings from this study were published on February 6, 2026, in the journal Icarus, contributing to our ongoing exploration of celestial phenomena.
