Astronomers analyzing data from the NSF–DOE Vera C. Rubin Observatory have discovered the fastest-spinning asteroid with a diameter over half a kilometer ever observed. This discovery marks the first scientific result obtained using the LSST Camera—the world's largest digital camera—to be published in a peer-reviewed journal (The Astrophysical Journal Letters).

Record-Breaker 2025 MN45

During the analysis of data collected during the telescope's commissioning phase (April–May 2025), scientists identified asteroid 2025 MN45.

In addition to this record-breaker, the team discovered 19 other super- and ultra-fast rotators and confirmed the existence of about 1,900 previously unknown asteroids.

Why Is This Important?

An asteroid's rotation speed provides clues about its internal structure. Most asteroids are so-called "rubble piles"—accumulations of debris held together by weak gravity. The spin limit for such objects is about 2.2 hours; if they spin faster, centrifugal force tears them apart.

The fact that 2025 MN45 rotates every two minutes without disintegrating means it possesses high internal strength. It is likely not a "rubble pile," but a monolithic fragment of solid rock.

Technological Breakthrough

Most previously known "fast" asteroids were found near Earth. Detecting such an object in the more distant Main Belt was made possible only by the unique sensitivity of the LSST Camera.

In the coming months, the observatory will begin its main 10-year Legacy Survey of Space and Time (LSST), during which it will image the sky every 40 seconds. Scientists expect this to lead to an avalanche of new discoveries, shedding light on the evolution of the Solar System.

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