Initial data from the Vera C. Rubin Observatory is already yielding surprising insights into our solar system, with astronomers reporting the discovery of 19 asteroids spinning at unexpectedly high speeds [[1]]. The findings, released today, suggest that current understandings of asteroid rotation-and the forces governing their evolution-may require considerable revision. These observations, made possible by the observatory’s wide-field survey capabilities, mark an early return on investment for the ambitious project which began full operation in late 2025.
New Observations Reveal Surprisingly Fast-Spinning Asteroids
Astronomers have identified 19 asteroids rotating at speeds previously thought rare for objects in the main asteroid belt. The findings, based on initial data from the Vera C. Rubin Observatory, suggest current models of asteroid rotation may need revision. This discovery underscores the ongoing effort to understand the formation and evolution of our solar system and the forces that shape celestial bodies.
The research team was able to determine more precise rotational rates for 75 asteroids in total. Among these, 19 asteroids, despite being several hundred meters in size, complete a full rotation in less than 2.2 hours. Five of these asteroids have rotational periods of less than 13 minutes, according to the team’s report.
The fastest-spinning asteroid discovered is 2025 MN45, measuring approximately 710 meters in diameter. “With a rotational period of only 1.9 minutes, it is the fastest rotating asteroid of this size class,” the astronomers write. It is among the fewer than a dozen ultra-fast rotating asteroids known to exist in the solar system.
Calculations indicate these rapidly rotating asteroids must withstand immense centrifugal forces exceeding 12 kilopascals. “The ultra-fast asteroids MK41 and MN45 must even exhibit cohesive forces of around 900 and 9,000 kilopascals, respectively, to avoid fragmentation,” explain the researchers. This suggests these asteroids are not simply “flying rubble piles” but are composed of solid rock.
Challenging Existing Theories
The sheer number of fast rotators identified in this initial survey with the Rubin Observatory was unexpected, the astronomers noted. “This suggests that we need to refine our understanding of the origin and evolution of asteroid rotations,” they write. Previously, rapid rotation was considered a rare phenomenon typically resulting from violent collisions. “But collisions may not be the only trigger for such ultra-fast rotational periods,” the team explains.
Further observations with the Rubin Observatory are expected to provide more insight into why more asteroids than anticipated are spinning so quickly. “As we obtain more data from the long-term survey with this telescope starting in early 2026, the number of measured asteroids will also increase,” the researchers state. “This could help to find further causes of such ultra-fast rotations.” doi: 10.3847/2041-8213/ae2a30
Source: Vera C. Rubin Observatory , NOIRLab, Association of Universities for Research in Astronomy (AURA)
9. January 2026
