Earlier this year, an asteroid collided with Earth's atmosphere, and research revealed that it spins approximately once every 2.6 seconds, faster than any other known asteroid. The findings were published on the preprint server arXiv on April 5th.
The trajectory of the asteroid 2024 BX1 shortly before impacting the atmosphere, with the variations in brightness in the image caused by the asteroid's rotation. Image credit: L. Buzzi, Schiaparelli Astronomical Observatory, Italy (MPC 204)
The asteroid known as 2024 BX1, possibly less than 1 meter wide, entered Earth's atmosphere on January 21 and disintegrated over Berlin, Germany. Some fragments survived the entry and were recovered. This rare instance provides a glimpse into tracking the fall of an asteroid, with the incoming rock being detected three hours before impacting Earth.
Maxime Devogele and colleagues at the European Space Agency's Near-Earth Object Coordination Centre in Italy captured images of the asteroid before it hit the atmosphere. Despite moving at speeds of around 50,000 kilometers per hour, its elongated shape highlighted brightness variations caused by rotation in these images.
These brightness changes correspond to a rotation period of 2.588 seconds—rotating about 30,000 times a day. "This is the fastest rotation we have observed," Devogele stated.
Asteroids rotate for various reasons, such as collisions in their early life. Generally, space rocks larger than 1 kilometer rotate no more than once every 2.2 hours, as they tend to break apart. However, smaller asteroids like 2024 BX1 can endure faster rotations due to their compact nature. "They have internal forces, so they rotate faster," Devogele explained.
Measuring the rotation of celestial bodies like this is valuable for planetary defense, providing insights into the strength of an asteroid and the likelihood of it passing through Earth's atmosphere.
For more information, refer to the related paper: https://doi.org/10.48550/arXiv.2404.04142
