Record-Breaking Asteroid Spins So Fast It Should Tear Itself Apart

With data collected months before the start of its main survey, the Vera C. Rubin Observatory is already turning what we thought we knew about asteroids on its head.

inside Main Belt of Asteroids between orbits Anthem And Jupitertelescope detected something big asteroid It spins surprisingly fast. Name 2025 MN₄₅It has a diameter of 710 meters (2330 feet) and a rotation time of only 1.88 minutes.

This is far, far beyond the 2.2-hour return barrier; beyond that, asteroids larger than 150 meters must fly into the pebbles as centrifugal forces supersede the asteroid’s so-called structural integrity.

Moreover, observations detected 18 additional asteroids orbiting at ‘impossibly’ high speeds. These results suggest that asteroids may be much more powerful than scientists previously thought.

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“The unexpected prevalence of asteroids that are several football fields long (greater than 500 meters in diameter) and complete a full rotation in less than two minutes requires us to improve our understanding of the formation and evolution of asteroid rotations.” a team writes It is led by astronomer Sarah Greenstreet of the US National Science Foundation’s National Optical-Infrared Astronomy Research Laboratory.

There’s more to the Solar System minor planets – well, a lot of things these are smaller than full-fledged planets, and not just comets, but smaller than anything else. These objects are usually protected pristine records Composition of the Solar System since its formation.

However, it is not easy to examine them. They are quite small, dark and distant and move around a lot. This means that detailed catalogs of their properties such as size, shape, and rotation are difficult to obtain.

Part of Rubin’s mission will be to create a more detailed inventory of asteroids than ever before, significantly expanding our understanding of these ancient, mysterious objects.

The telescope hit the ground running during the pre-survey observation period. For decades, astronomers thought they had a good understanding of how fast asteroids could safely orbit without breaking apart. This is because most asteroids are ‘piles of rubble‘ – collection of pebbles, dust and rocks loosely bound by gravity.

If one of these piles of debris rotates too quickly, this loose coupling is overcome by centrifugal force. think about it gravitronand the way people using it are thrown against the wall as it spins.

If you put a single, large, sticky mass at the center of the gravitron, that mass will stay in place. If the mass consisted of smaller components weakly held together, it would fall apart.

For the Large Main Belt asteroids, this breakup point is set at a rotation period of approximately 2.2 hours; this is a clear limit In the 1990s the theory was proposed by and later Confirmed in 2000 Observations of the Main Belt showed the existence of very few objects larger than 150 meters and with a rotation period shorter than this threshold.

The implication was that most asteroids were essentially rubble, and although more solid objects existed, they were thought to be few and far between.

Rubin’s observing campaign took place for nine nights between April 21 and May 5, 2025, collecting information on approximately 340,000 asteroids during this time. Drawing on this wealth of data, Greenstreet and his colleagues measured the rotation of 76 asteroids; 75 of these were hanging in the Main Belt and one in near-Earth space.

Nineteen of these asteroids had rotation periods shorter than the spin barrier: 16 were superfast rotators ranging from 2.2 hours to 13 minutes, and the remaining three were ultrafast rotators with periods less than five minutes.

This is a huge surprise: Most of the fast spinners discovered to date are near-Earth asteroids, closer to the Sun. Main Belt asteroids were thought to be much slower and more stable. Only one of the new fast spinners was a near-Earth object.

2025MN₄₅ It’s obviously one of the record breakers, but other asteroids can’t be ignored either. The fact that such a large percentage of the sample defies the spin barrier implies that we may have dramatically underestimated the number of Main Belt asteroids with high density and structural integrity.

“It’s clear that the asteroid must be made of very high-strength material to remain in one piece while spinning so fast.” greenstreet says. “We calculate that it would need an adhesive force similar to that of solid rock.”

This is extremely exciting. Solid pieces of rock like these may be survivors of unusually violent collisions in the chaos that reigned in the early Solar System, preserving internal structures that most asteroids lost long ago.

This bodes well for future Rubin observations. missions like lucyA NASA spacecraft that continues to explore asteroids up close.

“With potentially unusual compositions, internal structures and/or formation histories” researchers write“A much larger sample of these extremely fast-spinning asteroids would transform our understanding of the physical structure and collision histories of asteroids, and substantially our understanding of the formation and evolution of the Solar System.”

The findings were published at: Astrophysics Journal Letters.

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