The Vera C. Rubin Observatory is already redefining our understanding of the solar system, beginning with the discovery of a record-breaking asteroid that challenges existing theories on celestial composition. According to research published on January 7, 2026, in The Astrophysical Journal Letters, astronomers have identified asteroid 2025 MN45, a main-belt object with a diameter of approximately 710 meters that completes a full rotation in just 1.88 minutes.
This discovery, led by Sarah Greenstreet, an NSF NOIRLab assistant astronomer and head of the Rubin Observatory’s Near-Earth and Interstellar Object Working Group, marks the fastest rotation ever recorded for an asteroid exceeding 500 meters in diameter. The findings were presented at the 247th meeting of the American Astronomical Society and are based on data collected during the observatory’s early commissioning phase between April and May 2025.
The extreme rotational speed of 2025 MN45 suggests a level of internal structural integrity comparable to hard rock. This represents a significant departure from the prevailing scientific consensus that most asteroids are “rubble piles”—loose collections of debris held together by gravity, which typically have a much lower rotational speed limit.
This breakthrough is part of a larger surge in data from the facility. During a “First Look” event on June 23, 2025, the observatory revealed its first test images, which captured the light of millions of distant stars and galaxies, along with the discovery of over 2,000 previously unknown asteroids. Further analysis of this early data provided reliable rotation measurements for 76 asteroids, including 16 “ultra-prompt” rotators (periods between 13 minutes and 2.2 hours) and three “hyper-fast” rotators with periods under five minutes. All 19 of these high-speed asteroids are larger than a standard American football field.
Located at Cerro Pachón in the Andes Mountains of Chile, the powerful latest Rubin Observatory has discovered 11,000 new asteroids and measured tens of thousands more, signaling a new era of cosmic surveillance. Funded by the U.S. National Science Foundation (NSF) and the Department of Energy (DOE) Office of Science, the facility took nearly 20 years to construct.
The observatory’s capabilities are designed for an unprecedented scale of observation. Early test imagery, composed of 678 photos taken over 10 hours, has already produced clear views of the Trifid and Lagoon Nebulae. While early videos have showcased the detail of 10 million galaxies, the facility is expected to eventually observe a total of 20 billion.
The project reached a critical milestone on July 4, 2025, with the completion of main mirror calibration and the commencement of “first light,” marking the start of formal scientific operations. Brian Stone, Acting Director of the NSF, emphasized the project’s impact, stating, “Rubin Observatory will capture more cosmic information than all optical telescopes in history combined.”
