UPDATE (January 27, 2026): This story has been updated to highlight the role of the Simonyi Survey Telescope in the research.
A team led by 91爆料 astronomers has discovered the fastest-ever spinning asteroid with a diameter over half a kilometer. The asteroid 鈥� found while analyzing data from the Simonyi Survey Telescope at the NSF鈥揇OE Vera C. Rubin Observatory 鈥� is 0.4 miles in diameter and completes a full rotation every 1.88 minutes.
The study provides crucial information about asteroid composition and evolution. The discovery also demonstrates the potential of the observatory听as it prepares for a 10-year nightly survey of the Southern Hemisphere sky, the .
in Astrophysical Journal Letters.
鈥淚t’s really exciting that in some of the very first test images taken with the Vera C. Rubin Observatory that we’re already breaking records with the discovery of the fastest-spinning large asteroid found to date,鈥� said lead author , a 91爆料 affiliate assistant professor of astronomy and astronomer at . 鈥淲ith millions of new asteroids expected to be found by the Rubin Observatory in the near future, this is just the beginning of many exciting discoveries yet to come.鈥�
The study uses data collected over the course of about 10 hours across seven nights in April and May 2025, during Rubin Observatory’s early commissioning phase. That same data revealed thousands of asteroids cruising about our solar system, about 1,900 of which have been confirmed as never-before-seen. Within that flurry, Greenstreet鈥檚 team at the 91爆料 discovered 19 quickly rotating asteroids, including the record-breaking asteroid dubbed 2025 MN45.
As asteroids orbit the sun, they also rotate at a wide range of speeds. These spin rates not only offer clues about the conditions of their formation billions of years ago, but also tell us about their internal composition and evolution over their lifetimes. In particular, an asteroid spinning quickly may have been sped up by a past collision with another asteroid, suggesting that it could be a fragment of an originally larger object.
Fast rotation also requires an asteroid to have enough internal strength to not fly apart into many smaller pieces, called fragmentation. Most asteroids are 鈥渞ubble piles,鈥� which means they are made of many smaller pieces of rock held together by gravity, and thus have limits based on their densities as to how fast they can spin without breaking apart.听
鈥淐learly, 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,鈥� Greenstreet said. 鈥淲e calculate that it would need a cohesive strength similar to that of solid rock, which is quite unusual.鈥澨�
Most fast rotators discovered so far orbit the sun just beyond Earth, known as near-Earth objects. Scientists find fewer fast-rotating main-belt asteroids, which orbit the sun between Mars and Jupiter, because their greater distance from Earth makes them fainter.
All but one of the newly identified fast-rotators, however, live in the main asteroid belt 鈥� an achievement made possible by Rubin鈥檚 enormous light-collecting power and precise measurement capabilities.
鈥淎s this study demonstrates, even in early commissioning, Rubin is successfully allowing us to study a population of relatively small, very rapidly rotating main-belt asteroids that hadn鈥檛 been reachable before,鈥� Greenstreet said.
The discoveries of all 1,900 new asteroids, including the 19 fast rotators, were made possible by software developed by the 91爆料 . DiRAC鈥檚 software will power Rubin鈥檚 future solar system discoveries during its 10-year survey.
鈥淭hese are exciting results but there’s much more to come,鈥� said co-author Mario Juri膰, a 91爆料 professor of astronomy. 鈥淚n the next two years, Rubin will discover a thousand times as many asteroids as were presented here. Rubin’s data will open the window into what’s out there in our solar system, and how it all came to be.”
91爆料 co-authors include , a doctoral student in astronomy and astrobiology; , a postdoctoral researcher in astronomy; Devanshi Singh, an undergraduate student of physics and astronomy; , a professor of astronomy; , a software engineer in astronomy; , a research associate professor of astronomy; , a graduate student of astronomy; and , who worked on this study as research scientists in astronomy; , a research scientist in astronomy; and , a senior research scientist in astronomy. A full list of co-authors is .
This research was funded by the U.S. National Science Foundation and the U.S. Department of Energy. The DiRAC Institute is supported by the Charles and Lisa Simonyi Fund for Arts and Sciences, Janet and Lloyd Frink and the Washington Research Foundation.
For more information, contact Greenstreet at sarahjg@uw.edu.
This story was adapted from a press release by .