--- title: "Scientists Stumped by Why Mysterious Object Is Accelerating as a Japanese Spacecraft Rushes to Catch It" description: "There's something off about 1998 KY26, a mysterious object that the Japanese space agency's Hayabusa2 spacecraft is on its way to visit." date: "2026-11-09" modified: "2026-11-09" authors: - name: "Victor Tangermann" job_title: "Senior Editor" link: "https://futurism.com/authors/victor.md" url: "https://futurism.com/space/mysterious-object-accelerating-space" categories: - "Astronomy" - "Off-World" - "Space" --- # Scientists Stumped by Why Mysterious Object Is Accelerating as a Japanese Spacecraft Rushes to Catch It ![A render of JAXA's Hayabusa2 spacecraft landing on a suspected dark comet.]() *T. Santana-Ros et al.* There's something puzzling about 1998 KY26, a mysterious object that the Japanese space agency's Hayabusa2 spacecraft is on its way to visit: it's accelerating. That isn't necessarily out of the ordinary for asteroids and comets, but it appears to be driven by a propulsion source that scientists have yet to understand, as [*ScienceAlert* reports](). One explanation, from Harvard astronomer Avi Loeb, [suggests that 1998 KY26 is a derelict Soviet spacecraft]() that launched almost 40 years ago. More conventional attempts to account for its acceleration proffer that it's a "dark comet," a type of space object that acts like a rocky asteroid, but experiences acceleration that can't be accounted for by gravitational forces. Yet according to [new research]() published in the journal *Icarus*, it's too warm to be a dark comet, which can accelerate by releasing ice that sublimates into gas. If that were the case, observations show that it would've run out of ice reserves a long time ago. "Our temperature model results indicate that the water outgassing rate on 1998 KY26 would be too high to maintain buried ice, refining the understanding of the asteroid's composition," authors of the paper and Georgia Institute of Technology aerospace engineers Korbin Hansen and Masatoshi Hirabayashi wrote. 1998 KY26 is a 36-foot space object that rotates every five and a half minutes and is currently located [186 million miles]() away from Earth. After modeling its temperature using pre-existing data, Hansen and Hirabayashi found that even its coldest regions measured upwards of -77 degrees Fahrenheit. While that may sound chilly, it's too warm for stores of ice that could sublimate into gas and provide thrust. At such warm temperatures, 1998 KY26 would've run out of fuel in just 62 years, a blink of an eye for an object suspected to be billions of years old, as *ScienceAlert* points out. The team concludes that "1998 KY26 is likely a dehydrated asteroid," meaning that it lost its stores of water long ago. Other explanations for its acceleration could be solar radiation or "thermal emission forces" pushing it. Fortunately, Hayabusa2 is expected to rendezvous with the mysterious object in July 2031, which could give scientists a first-hand look at whatever is going on. **More on dark comets:** [*Paper Claims the “Asteroid” Japan’s Probe Is Approaching Is Actually a Derelict Spacecraft*]() ## Author I've been at Futurism since 2017, where my role has evolved to encompass design, writing, and increasingly editing. I've always been fascinated by space exploration and advanced transportation, which I've leaned into by interviewing luminaries in those fields while closely following the dimensions of policy and regulation that allow next-generation projects to succeed -- or, sometimes, to fail. I'm also keenly interested in the effects of generative AI on society, policies, and democratic institutions, as well as clean energy, physics and biology, and the vagaries of tech leadership. My work for Futurism has been cited by publications including Ars Technica, Gizmodo, PC Magazine, Jalopnik, Fox News, and the New York Post. I spent my childhood living in locations including Manila, the Philippines, and Geneva, Switzerland, attended McGill University, and now live in Toronto, Canada. Before Futurism I worked at AskMen and a small photography studio. In my free time, I'm an avid gardener, foodie, and craft beer lover, as well as a maker of artisanal hot pepper sauces. I have a magnificent dog named Freida. ### Author social links [Bluesky]() ## More - [Paper Claims the “Asteroid” Japan’s Probe Is Approaching Is Actually a Derelict Spacecraft]() - [Scientist Says Mysterious Object Approaching Earth May Be Alien Artifact]() - [Mysterious Interstellar Object Showing Signs of “Non-Gravitational Acceleration”]() - [The Mysterious Object Cruising Toward Mars Is Doing Something Very Peculiar]() - [Nine Reasons This Scientist Is Suspicious the Object Screaming Past the Sun Is a City-Sized Alien Spacecraft]() - [Scientist Suggests Tests to See if Large Object Headed Toward Earth Could Be an Alien Spacecraft]() - [NASA Scientist Disputes Claim That Mysterious Object Headed Into Solar System Was Sent by Aliens]() - [Scientists Propose Interesting Explanation for Mysterious Signals From Space]()