Imagine an asteroid the size of eight football fields spinning faster than a blender on high speed—every two minutes. Sounds like science fiction, right? But it’s real, and it’s just one of the mind-boggling discoveries made by the NSF–DOE Vera C. Rubin Observatory during its pre-survey observations. This record-breaking find, detailed in the first peer-reviewed paper using data from the LSST Camera, isn’t just a cool factoid—it’s a game-changer for understanding asteroid composition, evolution, and the limits of what we can uncover in our Solar System.
Here’s where it gets even more fascinating: This asteroid, named 2025 MN45, is part of a group of 19 super- and ultra-fast-rotating asteroids spotted by Rubin. What’s truly astonishing is that 2025 MN45, with a diameter of 710 meters (0.4 miles), completes a full rotation every 1.88 minutes—making it the fastest-spinning asteroid larger than 500 meters ever observed. But how does it stay intact? Scientists believe its material must have a cohesive strength similar to solid rock, a surprising revelation since most asteroids are thought to be ‘rubble piles’ held together by gravity. And this is the part most people miss: This discovery challenges our understanding of asteroid structure and hints at a violent past, possibly involving collisions that accelerated its spin.
The Rubin Observatory, a joint project of the U.S. National Science Foundation (NSF) and the Department of Energy (DOE), is no ordinary telescope. Its LSST Camera, the largest digital camera in the world, is set to scan the Southern Hemisphere night sky for ten years, creating an ultra-wide, ultra-high-definition time-lapse of the Universe. During its early commissioning phase in April/May 2025, Rubin observed thousands of asteroids, about 1,900 of which were previously unknown. This isn’t just about spotting new rocks in space—it’s about rewriting the rules of what we thought was possible in astronomy.
But here’s where it gets controversial: As Rubin pushes the boundaries of observation, it’s uncovering asteroids spinning at speeds that were once thought impossible. For instance, the fast-rotation limit for main-belt asteroids to avoid fragmentation is 2.2 hours. Yet, 2025 MN45 spins more than 70 times faster than that! This raises questions: Are these asteroids made of stronger materials than we assumed? Or are our models of asteroid formation incomplete? These discoveries are forcing scientists to rethink everything from asteroid composition to the dynamics of collisions in space.
The study, led by Sarah Greenstreet of NSF NOIRLab, presents 76 asteroids with reliable rotation periods, including 16 super-fast rotators and three ultra-fast rotators. All but one of these fast-spinners reside in the main asteroid belt, a region where such rapid rotation is rarely observed due to the faintness of their light. Rubin’s unprecedented light-collecting power and precision are changing that, allowing us to study these distant objects in detail.
Here’s the bigger picture: When Rubin’s Legacy Survey of Space and Time (LSST) begins in the coming months, it will uncover countless more secrets. Unlike the dense, rapid observations that led to these initial discoveries, LSST’s regular scans will gradually reveal fast-rotating asteroids, providing critical insights into their strengths, compositions, and histories. As Luca Rizzi, an NSF program director, puts it, “Rubin will find things that no one even knew to look for.”
So, what does this mean for us? These discoveries aren’t just about asteroids—they’re about understanding the building blocks of our Solar System and the forces that shaped it. And as Rubin continues its mission, it’s not just astronomers who should be excited. Here’s a thought-provoking question for you: If these asteroids can spin so fast without breaking apart, what does that tell us about the resilience of materials in space? Could this knowledge inspire new technologies or materials here on Earth?
As we await the avalanche of data from LSST, one thing is clear: The Universe still has plenty of surprises in store, and Rubin is our ticket to uncovering them. Stay tuned—this is just the beginning.
