Posted on January 30, 2026
Astronomers have made an astonishing discovery thanks to the Vera C. Rubin Observatory in Chile: The fastest rotating large asteroid ever recorded. The asteroid 2015 MN45 has significantly changed how we view asteroids and their composition.
At 710 meters (0.44 miles) in diameter, 2015 MN45 is approximately the length of eight football fields long. What sets this asteroid apart is its speed of rotation. The asteroid makes a complete turn every 1.88 minutes the fastest recorded rotation of any large asteroid.
Most large asteroids spin considerably slower than 2015 MN45. In fact, most of the objects in the main asteroid belt – the area in between Mars and Jupiter in space, where 2015 MN45 is located take hours to make one rotation. Generally speaking, asteroids that rotate more than 2.2 hours will disintegrate due to the centrifugal force that exceeds the gravitational attraction between the objects.
What prevents asteroid 2025 MN45 from breaking apart due to its high rate of rotation? Its internal properties provide the answer. Astronomers believe that the asteroid consists of a dense material (for example, solid rock); this is opposed to the majority of the other asteroids in the asteroid belt, which are classified as “rubble piles,” consisting of many loose individual fragments of rock and/or dust held together only by the force of gravity. This strength allows 2025 MN45 to sustain its cohesive integrity under the forces of a rapid rate of spin without breaking apart.
The data were collected as part of the First Look program, using the advanced technology of the Legacy Survey of Space and Time (LSST) project at the Rubin Observatory. Thousands of images were taken over several nights in 2025 by the LSST telescope. Included within this vast quantity of data are many other objects that rotated quickly, which leads researchers to suspect that these fast-rotating Asteroids may exist in greater numbers than previously recognized.
One of the beneficial characteristics of the Rubin Observatory is its ability to collect repeated observations of large sections of the night sky in high-resolution detail. The observatory’s 3.2-billion-pixel camera can easily capture many faint and distant objects not picked up by other telescopes, making the LSST an essential research tool for studying the smaller members of our Solar System.
What makes the discovery of asteroids like 2025 MN45 relevant? Understanding the formation and evolution of our Solar System is only made possible through studying these rocks, which provide scientists with information about their history (like collisions), speed and size, and composition.
Also, understanding the behavior of asteroids enables scientists to better identify and assess the risks associated with them as well as provide improved predictions for tracking these objects.
Astronomers will continue discovering exciting new evidence as the Rubin Observatory undergoes its formal survey starting in 2026. In the meantime, 2025 MN45 is an excellent example of the information scientists can still gather about the small but interesting celestial bodies orbiting our Sun.