January 9, 2026

The astronomical community is buzzing with the formal release of data from the Vera C. Rubin Observatory in Chile, revealing the discovery of an absolute titan among “fast-rotators.” In a peer-reviewed study appearing in The Astrophysical Journal Letters and presented at the 247th meeting of the American Astronomical Society (AAS) in Phoenix, astronomers confirmed the existence of 2025 MN45—a massive asteroid that completes a full rotation in a staggering 1.88 minutes. Measuring approximately 710 meters (0.44 miles) in diameter, or nearly the size of eight American football fields, this celestial body has officially shattered the record for the fastest-spinning asteroid ever discovered with a diameter over half a kilometer.

The Record-Breaking Discovery

The discovery of 2025 MN45 was made possible by the 3.2-gigapixel LSST Camera, the world’s largest digital camera, during the observatory’s “First Look” commissioning phase. While smaller asteroids are known to spin rapidly, larger objects like this one typically face a “speed limit.” Most asteroids in the Main Asteroid Belt, located between Mars and Jupiter, are “rubble piles”—loose collections of rock held together only by gravity. For an object of this size, spinning faster than once every 2.2 hours would normally cause it to fly apart. However, 2025 MN45 is spinning 70 times faster than that limit, suggesting it is a single, solid piece of extremely strong rock.

Expert Statements

Lead author and NSF NOIRLab assistant astronomer Sarah Greenstreet highlighted the sheer violence and physical requirements of such a body: “Clearly, this asteroid must be made of material that has very high strength in order to keep it in one piece as it spins so rapidly. We calculate that it would need a cohesive strength similar to that of solid rock. This is somewhat surprising since most asteroids are believed to be what we call ‘rubble pile’ asteroids.” Greenstreet further theorized on the object’s origin, stating, “We also believe that it’s likely a collisionary fragment of a much larger parent body that, early in the solar system’s history, was heated enough that the material internal to it melted and differentiated.”

Echoing the technological triumph, Luca Rizzi, an NSF program director, noted the observatory’s future potential: “NSF–DOE Rubin Observatory will find things that no one even knew to look for. When Rubin’s Legacy Survey of Space and Time begins, this huge spinning asteroid will be joined by an avalanche of new information about our Universe, captured nightly.” Aaron Roodman, Deputy Head of LSST, added, “We have known for years that Rubin would act as a discovery machine for the universe, and we are already seeing the unique power of combining the LSST Camera with Rubin’s incredible speed. Together, Rubin can take an image every 40 seconds.”

Scientific Significance

Beyond its record-breaking speed, the discovery of 2025 MN45 provides a rare window into the collisional history of our solar system. Scientists believe that a primordial collision must have blasted this object from the dense, differentiated core of a much larger parent body, sending it whirling into space. This find is part of a larger cohort of 19 super- and ultra-fast-rotating asteroids identified by the Rubin team, 18 of which reside in the Main Belt. Historically, such fast-spinners were only seen near Earth because they were easier to spot; the Rubin Observatory’s enormous light-collecting power now allows us to see these “spinning tops” at much greater distances, fundamentally changing our understanding of asteroid composition and the physical limits of celestial objects.