SANTIAGO, Chile, January 10 — Astronomers have identified the fastest-spinning large asteroid ever observed, a finding that challenges current understanding of how such space rocks hold together. The asteroid, named 2025 MN45, is 2,300 feet in diameter yet completes a full rotation every 1.88 minutes.
What happened with asteroid 2025 MN45?
The discovery was made using the Vera C. Rubin Observatory in Chile. Its powerful camera spotted 19 rapidly rotating asteroids in the main Asteroid Belt between Mars and Jupiter. The study, published in The Astrophysical Journal Letters, details 76 asteroids, with 16 classified as super-fast rotators.
- 2025 MN45 is the fastest among rocks larger than 500 meters.
- Its spin speed should, in theory, cause it to break apart.
Lead author Sarah Greenstreet said the asteroid must be made of exceptionally strong material to remain intact. “This is somewhat surprising since most asteroids are believed to be what we call ‘rubble pile’ asteroids,” she noted in a statement.
Why does this discovery matter now?
The spin rate of an asteroid acts like a historical record. It can tell scientists about the rock’s formation, composition, and the collisions it has endured. Finding an ultra-fast rotator this large forces a re-evaluation of asteroid strength and structure. The Rubin Observatory’s survey is just beginning, promising more such revelations about our solar system’s history.
How did the Rubin Observatory make this possible?
The observatory houses the world’s largest digital camera, giving it an unprecedented ability to detect faint, fast-moving objects. “Rubin is successfully allowing us to study a population of relatively small, very-rapidly-rotating main-belt asteroids that hadn’t been reachable before,” Greenstreet explained. This new window into the asteroid belt will help map the population and collisional history of these objects in greater detail.
What comes next for this research?
The formal Legacy Survey of Space and Time (LSST) at the Rubin Observatory begins this year. This decade-long project will scan the entire southern sky repeatedly. Scientists expect it to discover thousands more asteroids, potentially including other ultra-fast rotators. This will enable them to determine if 2025 MN45 is a singular anomaly or a member of a broader, unobserved class of solid asteroids.
FAQs
Q: How fast is asteroid 2025 MN45 spinning?
A: It is the fastest-spinning big asteroid known, completing a full rotation every 1.88 minutes.
Q: Where is this asteroid located?
A: It is in the main Asteroid Belt, the region of space between the orbits of Mars and Jupiter.
Q: Why doesn’t it fly apart at that speed?
A: Scientists led by Sarah Greenstreet conclude it must be made of solid, high-strength rock, unlike many “rubble pile” asteroids.
Q: How was it discovered?
A: It was spotted by the Vera C. Rubin Observatory in Chile during its early survey work.
