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Far beyond the orbit of Neptune, in the cold and dark edges of our solar system, lies a vast region called the Kuiper Belt. This area is home to Pluto and countless other icy bodies known as planetesimals. For many years, scientists noticed something strange about these objects. A surprising number of them have a peculiar shape. They look like snowmen, made of two rounded balls connected together. Astronomers call these structures "contact binaries." Data shows that about one out of every ten Kuiper Belt objects has this two-part shape. For a long time, researchers asked how such a specific shape could exist so far from the Sun.
On February 19, 2026, a team of researchers from Michigan State University shared a possible explanation for this common shape. Their findings suggest the cause is surprisingly simple and comes from the basic forces of nature. Jackson Barnes, the lead author of the study, used advanced computer simulations to explore the origins of these objects. He used the powerful High-Performance Computing Center at the university's Institute for Cyber-Enabled Research to run complex models. These simulations showed that creating snowman-shaped objects does not rely on rare chance collisions or strange cosmic events. Instead, the process appears to be a natural result of gravitational collapse.
Seth Jacobson, a co-author of the study, emphasized the importance of how often this happens. He noted that because so many planetesimals are contact binaries, the method that creates them cannot be a rare accident. Jacobson stated, "If we think 10% of planetesimal objects are contact binaries, the process that forms them can't be rare. Gravitational collapse fits nicely with what we've observed." This view changes how we understand these objects, moving from a matter of lucky accidents to a predictable physical process.
The most famous example of such an object is Arrokoth. Before the recent simulations, this distant world gave us our first close-up look at a contact binary. The New Horizons spacecraft flew past the rocky snowman on New Year's Day in 2019. The images sent back by the probe revealed a stunning, perfectly connected dual shape that had survived for billions of years in the outer solar system. The researchers published their paper in the journal Monthly Notices of the Royal Astronomical Society on February 19, 2026. Their work provides a new way to understand the early history of our solar system.
The computer simulations required by the research team needed to explain how contact binaries could form regularly. Also, the models had to show that these objects keep their unique shapes over billions of years. Many previous computer models failed to meet these criteria. They often produced objects that eventually merged into a single, blob-like shape, losing the distinct two-part structure. Barnes' simulations, however, allowed the snowmen to keep their characteristic form. This success suggests that the gravitational collapse process is stable enough to preserve the snowman shape against forces that might otherwise flatten or destroy it.