Harvard Scientist Says 1998 KY26 Is Not an Asteroid

Harvard astrophysicist Avi Loeb is disputing NASA’s assessment of a mysterious space object known as 1998 KY26, declaring that the accelerating body is “not an asteroid.”

The near-Earth object measures roughly 11 meters across. It reflects nearly 52 percent of incoming sunlight. It completes a full rotation every 5.35 minutes. While space agencies and researchers study its unexpected non-gravitational acceleration, scientists remain deeply divided.

Debating the Nature of 1998 KY26

Discovered on May 28, 1998, by the Spacewatch astronomical survey program, 1998 KY26 was categorized as a near-Earth asteroid. European Space Agency database data revealed that it took 498 Earth days to complete a single orbit around the Sun. Observations indicate it is located 186 million miles away from Earth.

Recent measurements show the object is speeding up in a way that the gravity of the Sun and planets cannot fully explain. NASA Administrator Jared Isaacman addressed the speculation during an appearance on “Fox & Friends,” stating that he had seen no evidence to suggest the object is anything other than an asteroid or a threat to Earth.

“I have no reason to believe this is in any way remotely a threat to our planet or anything other than just an asteroid,” said Administrator Jared Isaacman.

Loeb pushed back against that classification during an interview with Fox News Digital, pointing to the object’s anomalous movement. “Well, first of all, it’s not an asteroid because 1998 KY26 appears to have non-gravitational acceleration, meaning it’s being pushed by some force other than gravity, and asteroids are just rocks,” Loeb said.

Testing the Soviet Spacecraft Hypothesis

Loeb has advanced an unconventional alternative hypothesis alongside colleague Adam Hibberd. He also worked with Adam Crowl. They suggested that 1998 KY26 could actually be Phobos 1. That was an uncrewed Soviet probe launched on July 7, 1988, that lost communication with Earth two months into its journey toward Mars.

The researchers built a simplified model of the lost spacecraft. They found that its light curves matched across eight separate observation sets of the accelerating object. The researchers tested whether sunlight pushing against a cylinder or solar panels could explain the object’s movement. They found the model matched hundreds of telescope and radar observations.

Before this hypothesis gained traction, researchers explored whether 1998 KY26 could be a “dark comet”—an inactive-looking body holding buried ice that sublimates into thrust-generating gas without producing a visible tail or coma. That idea faced a hurdle following a peer-reviewed study published in the journal Icarus by Georgia Institute of Technology researchers Korbin Hansen and Masatoshi Hirabayashi.

The engineers calculated that even the coldest regions of 1998 KY26 maintain an orbit-averaged temperature of at least 212 Kelvin. That temperature is -78.7°F. Those numbers make the object too warm to retain the buried water ice necessary to power cometary outgassing.

“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,” the researchers said.

Hayabusa2 Rendezvous Set for 2031

NASA maintains that a comprehensive orbital analysis completed in 2025 concluded the object’s behavior is driven by standard solar radiation forces rather than hidden comet-like activity or artificial propulsion. Meanwhile, the Japan Aerospace Exploration Agency is preparing to resolve the debate directly.

The Hayabusa2 spacecraft previously visited the asteroid Ryugu and returned samples to Earth. It is en route to 1998 KY26 as its final target. The Japan Aerospace Exploration Agency expects the probe to rendezvous with the object in July 2031 to conduct close-range observations of the tiny body.

“The destination will be the small asteroid 1998 KY26. This is a long-term mission that exceeds 10 years and, after an itinerary of various events, we aim to rendezvous with the rapidly rotating 1998 KY26,” the Japan Aerospace Exploration Agency announced.

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