Rubin Observatory finds fastest-spinning large asteroid ever recorded

What happened: The Vera C. Rubin Observatory has detected asteroid 2025 MN45, a 710-metre-wide object spinning once every 1.88 minutes.

• Why it matters now: Such rapid rotation challenges current models of how large asteroids hold together.

• What changes for people: The discovery strengthens early-warning research and helps scientists refine impact-risk assessments.

• Who is affected: Astronomers, planetary-defence teams and agencies studying near-Earth objects.

A new discovery by the Vera C. Rubin Observatory has stunned astronomers after researchers confirmed that asteroid 2025 MN45, a body nearly three-quarters of a kilometre wide, completes a full rotation in just 1.88 minutes. The finding makes it the fastest-spinning large asteroid ever observed, pushing the limits of what scientists believed such massive objects could physically withstand.

Experts note that an asteroid of this size should normally break apart if it were a typical rubble pile made of loosely bound fragments. Instead, its behaviour points to a far denser, solid-rock composition, offering valuable clues about how some asteroids formed in the early Solar System.

Why the discovery matters

Planetary-defence researchers say unusually fast-spinning asteroids help refine understanding of structural integrity, an essential factor when modelling potential impact scenarios. Because the object displays high cohesion, it may respond differently to deflection or mitigation strategies compared with weaker bodies.

The observatory team highlighted that rapid-rotation asteroids of this scale are extremely rare, making 2025 MN45 an important target for further study. Its composition could reveal how primordial collisions shaped today’s asteroid population.

Broader scientific implications

The Rubin Observatory’s early detection pipeline is designed to improve the global ability to track hazardous near-Earth objects. This latest discovery reinforces the role of high-cadence sky surveys in identifying unusual bodies that could influence long-term modelling of Solar System evolution.

Researchers are now preparing follow-up observations to confirm density, internal strength and thermal properties. The results may reshape assumptions used in both academic research and international preparedness planning.