{"id":228165,"date":"2026-01-11T12:05:12","date_gmt":"2026-01-11T12:05:12","guid":{"rendered":"https:\/\/www.newsbeep.com\/nz\/228165\/"},"modified":"2026-01-11T12:05:12","modified_gmt":"2026-01-11T12:05:12","slug":"fast-spinning-asteroid-2025-mn45-rewrites-rotation-record","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/nz\/228165\/","title":{"rendered":"Fast-spinning asteroid 2025 MN45 rewrites rotation record"},"content":{"rendered":"

\"Fast-spinningThis artist\u2019s illustration depicts the fast-spinning asteroid 2025 MN45. It\u2019s the fastest-rotating asteroid with a diameter greater than 500 meters (0.3 miles) that scientists have yet found; 2025 MN45 is 710 meters (0.44 miles) in diameter. The asteroid, which resides in the asteroid belt<\/a>, completes a full rotation every 1.88 minutes. The NSF\u2013DOE Vera C. Rubin Observatory<\/a> made the discovery. And that\u2019s the sun and Jupiter in the distance. Image via NSF\u2013DOE Vera C. Rubin Observatory\/ NOIRLab<\/a>\/ SLAC\/ AURA\/ P. Marenfeld.<\/p>\n

EarthSky\u2019s 2026 lunar calendar shows the moon phase for every day of the year. Available now. Get yours today!<\/a><\/p>\n

Fast-spinning asteroid 2025 MN45 rewrites rotation record<\/p>\n

The Vera C. Rubin Observatory<\/a> has just discovered a \u201cnever before seen\u201d fast-spinning asteroid. It sets a new speed standard for solar system objects larger than .5 kilometer (0.3 miles). NOIRLab said<\/a> on January 7, 2026, that the asteroid \u2013 named 2025 MN45 \u2013 measures a whopping 710 meters (0.44 miles) and makes a full rotation every 1.88 minutes!<\/p>\n

The whirling rocky body is one of 1,900 new solar system objects discovered during Rubin\u2019s First Look Event<\/a> in spring 2025. Among the freshly found minor planets<\/a> were 19 super- and ultra-fast-rotating asteroids. 2025 MN45 lies in the main asteroid belt<\/a>.<\/p>\n

The Astrophysical Journal Letters published<\/a> the peer-reviewed<\/a> study on January 7, 2026.<\/p>\n

Fast-spinning asteroid made of very strong stuff<\/p>\n

Most main-belt asteroids are assemblages of small rocks loosely held together by gravity. That means if they spin too quickly, they fly apart. Because fast-spinning 2025 MN45 makes one rotation in less than two minutes, it must be extremely solid. NOIRLab\u2019s press release said<\/a>:<\/p>\n

For objects in the main asteroid belt, the fast-rotation limit to avoid being fragmented is 2.2 hours; asteroids spinning faster than this must be structurally strong to remain intact. The faster an asteroid spins above this limit, and the larger its size, the stronger the material it must be made from.<\/p>\n

The other recently discovered fast-spinning objects must also be made of quite stern stuff. The 16 super-fast rotators have periods of between 13 minutes and 2.2 hours. The three ultra-fast rotators \u2013 including 2025 MN45 \u2013 all complete a rotation in less than 5 minutes.<\/p>\n

Sarah Greenstreet<\/a>, NOIRLab assistant astronomer and lead of Rubin Observatory\u2019s Solar System Science Collaboration\u2019s Near-Earth Objects and Interstellar Objects working group, described the composition of such a fast-spinning asteroid as unusual:<\/p>\n

We calculate that it would need a cohesive strength similar to that of solid rock. This is somewhat surprising since most asteroids are believed to be what we call \u2018rubble pile\u2019 asteroids, which means they are made of many, many small pieces of rock and debris that coalesced under gravity during solar system formation or subsequent collisions.<\/p>\n

Watch EarthSky\u2019s Dave Adalian discuss the world\u2019s most powerful camera inside the Vera C. Rubin Telescope with Steven Bellavia.<\/p>\n

1,900 asteroids discovered in about 10 hours<\/p>\n

NOIRLab, which operates the world\u2019s largest digital camera<\/a> at the Rubin Observatory, tested the equipment during a commissioning phase in spring of 2025. The results of that brief first-light<\/a> observation \u2013 approximately 10 hours of observing over seven nights in April and May \u2013 yielded a treasure trove of solar system objects.<\/p>\n

It also yielded the first study<\/a> based on data from the Rubin Observatory. The paper presents reliable rotation periods for 76 asteroids, including the 16 super- and three ultra-fast rotating objects. All 19 objects are longer than 90 meters (300 feet). And 2025 MN45 is the largest of those.<\/p>\n

\"YoungSarah Greenstreet<\/a>, NOIRLab assistant astronomer and lead of Rubin Observatory\u2019s Solar System Science Collaboration\u2019s Near-Earth Objects and Interstellar Objects working group. Image via University of Washington<\/a>.
\nRubin can see distant asteroids more clearly<\/p>\n

The majority of previously documented fast-spinning asteroids are near-Earth objects (NEOs<\/a>). This, however, was mainly because the distance to the main asteroid belt made them difficult to observe from Earth. According to NOIRLab\u2019s Greenstreet, the Rubin\u2019s oversize camera has significantly extended humanity\u2019s reach:<\/p>\n

As this study demonstrates, even in early commissioning, Rubin is successfully allowing us to study a population of relatively small, very-rapidly-rotating main-belt asteroids that hadn\u2019t been reachable before.<\/p>\n

Only one of the newly discovered fast-spinning asteroids is an NEO. The rest lie between the orbits of Mars and Jupiter, as far away as the outside edge of the main asteroid belt. Besides 2025 MN45, other fast-spinning asteroids of note described are 2025 MJ71 (1.9-minute rotation period), 2025 MK41 (3.8-minute rotation period), 2025 MV71 (13-minute rotation period) and 2025 MG56 (16-minute rotation period).<\/p>\n

Scientists expect many more fast-spinning asteroid discoveries once Rubin begins its decade-long Legacy Survey of Space and Time<\/a>. That ambitious project aims to take hundreds of high-resolution images every night of the Southern Hemisphere sky. The data collected should lead future study of the makeup and formation history of fast-spinning asteroids.<\/p>\n

Bottom line: 2025 MN45 \u2013 a newly discovered, fast-spinning asteroid \u2013 is the fastest-rotating object of its size scientists have yet discovered. It rotates once every 1.88 minutes.<\/p>\n

Source: Lightcurves, Rotation Periods, and Colors for Vera C. Rubin Observatory\u2019s First Asteroid Discoveries<\/a><\/p>\n

Via NOIRLab<\/a><\/p>\n

Read more: See the first Rubin Observatory images here!<\/a><\/p>\n

Dave Adalian
\n View Articles<\/a><\/p>\n

About the Author:<\/p>\n

Award-winning reporter and editor Dave Adalian’s fascination with the cosmos began during a long-ago summer school trip. That fieldtrip never ended, and still Dave pursues adventures under the night sky.
\n
\nDave grew up in California’s Tulare County – where the San Joaquin Valley meets the Sierra Nevada – a wilderness larger than Delaware and Rhode Island combined.
\n
\nHe studied English, American literature and mass communications at the College of the Sequoias and the University of California, Santa Barbara. He has worked as a reporter and editor for a variety news publications on- and offline during a career spanning more than 30 years.<\/p>\n","protected":false},"excerpt":{"rendered":"This artist\u2019s illustration depicts the fast-spinning asteroid 2025 MN45. It\u2019s the fastest-rotating asteroid with a diameter greater than…\n","protected":false},"author":2,"featured_media":228166,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[111,139,69,147,392],"class_list":["post-228165","post","type-post","status-publish","format-standard","has-post-thumbnail","category-space","tag-new-zealand","tag-newzealand","tag-nz","tag-science","tag-space"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/228165","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/comments?post=228165"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/228165\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media\/228166"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media?parent=228165"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/categories?post=228165"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/tags?post=228165"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}