Fastest Spinning Space Rock on Record? Asteroid 2024 BX1 That Blasted Over Berlin Had the Fastest Spin Among Near-Earth Objects

Scientists have found that asteroid 2024 BX1, which blasted over Berlin last January, had the fastest spin compared to other near-Earth objects that were even observed.

Asteroid 2024 BX1 Blasted Over Berlin

Earlier this year, the space rock 2024 BX1 became a fireball and blasted over Berlin. This happened during the early hours of January 21. Though tiny asteroids on the course of collision with Earth are typically only detected when they hit the atmosphere, this one was detected by scientists around three hours before the impact happened.

Now, on top of this oddity, a preprint paper now suggests that the space rock, which was moving at a rate of 50,000 kmph, had a rotation speed of 2.6 seconds. This is the fastest spin that has ever been observed in an asteroid.

Fastest Spin on Record

Before this, the fastest-spinning asteroid on record was the 2020 HS7. It exhibited a rotation period of just 2.99 seconds. This space rock spanned roughly 13 to 24 feet in diameter, making it slightly bigger compared to 2024 BX1. This size could also shed light on why the latter one had a faster spin.

There are various reasons why asteroids spin. Such reasons include propulsion back to space post-collision. Due to their higher degree of being compact, smaller asteroids usually have a faster spin compared to their larger counterparts. Maxime Devogèle, the study's lead author and a physicist from the University of Central Florida and who works with the ESA (European Space Agency), notes that these smaller asteroids have internal strength, enabling them to have a faster rotation.

Along with colleagues, Devogèle examined the rotational speeds of three space rocks. They made use of images that were taken as the rocks neared the Earth. Aside from the 2024 BX1, there were two other asteroids, 2024 EF and 2023 CX1, that were studied. These two were described based on their close calls with the Earth that were respectively recorded on March 4, 2024 and February 13, 2023.

The scientists were able to come up with a novel technique for visualizing the rotational speeds of asteroids. Such an approach involved modifying the aperture size in order to maintain the sharpness of the starry background and enable the asteroid to show up as a light trail.

Scientists may usually tune exposure time as they photograph asteroids in order for both the space region and the flying rock to stay quite crisp. However, near-Earth objects (NEOs), such as 2024 BX1, have an incredibly fast speed, requiring impossibly brief exposure times for them to look clear.

The researchers note that rather than monitoring the motion of the asteroid, they observed the rock with the use of sidereal tracking and allowed the asteroid to sweep across the field.

The long exposure time enabled the images to display the rock trailing against space. The paper notes that brightness changes across the path stress where the rotation happened and suggests a shape that is elongated. As the researchers examined the distance across the bright spots, they discovered that it corresponded to a period of rotation amounting to 2.588 seconds, which is equivalent to roughly 33,000 rotations each day.

The researchers note that the method's advantage is that it enables them to extract the object's brightness over time using single images.

Being able to know the rotational speeds of NEOs could help with risk mitigation, as these objects may pose threats to infrastructure and humans.

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