Astronomers Discover Fastest-Rotating Asteroid MM45 at 1.88 Minutes

Astronomers at the **Vera C. Rubin Observatory** have identified asteroid **MM45**, the fastest rotating asteroid of its size, completing a full rotation in just **1.88 minutes**. This discovery is part of a broader effort that has seen the observatory detect nearly **2,000 asteroids** over the past year, with 19 classified as super-fast or ultra-fast rotators.

Among these, MM45 stands out as the fastest known asteroid larger than **500 meters**, and its rapid spin raises intriguing questions about its composition. According to the observatory, fast rotation suggests that the asteroid must possess significant internal strength to avoid disintegration. Most asteroids are typically described as “rubble piles,” composed of smaller rocks held together by gravity.

Sarah Greenstreet, a researcher with the **National Optical-Infrared Astronomy Research Laboratory (NOIRLab)**, stated, “Clearly, 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.” She explained that MM45 would need a cohesive strength similar to that of solid rock, which challenges previous assumptions about the structure of asteroids.

Another noteworthy asteroid discovered during this survey rotates every **1.9 minutes**, close behind MM45. The speed of these discoveries is remarkable, achieved in just **10 hours** of observations rather than the months typically required for such extensive surveys.

Significance of the Discovery

The discoveries made by the Vera C. Rubin Observatory are part of the **Legacy Survey of Space and Time (LSST)**, which aims to create the largest astronomical movie of the Southern Hemisphere night sky over a **10-year period**. The observatory, funded by the **National Science Foundation** and the **U.S. Department of Energy**, is named after the late astronomer **Vera Rubin**, who provided pivotal evidence for dark matter in the universe.

Aaron Roodman, Deputy Head of LSST and a professor of particle physics and astrophysics at **SLAC**, commented on the capabilities of the observatory. “We have known for years that Rubin would act as a discovery machine for the Universe, and we are already seeing the unique power of combining the LSST Camera with Rubin’s incredible speed,” he noted. The observatory can capture an image every **40 seconds**, allowing astronomers to identify thousands of new asteroids in a short time frame.

Researchers anticipate that the LSST will reveal even more about asteroids and other celestial objects, significantly enhancing our understanding of the **Solar System** and its formation. As the observatory gears up for full operations in **2026**, the excitement within the astronomical community continues to build over what further secrets the universe may hold.

The rapid rotation of MM45 and its classification as the fastest-known asteroid larger than 500 meters marks a significant milestone in asteroid studies, contributing valuable insights into the composition and behavior of these fascinating celestial bodies.