Berlin witnesses fastest spinning asteroid breakup in recorded history

The asteroid that entered Earth’s atmosphere this year was spinning at a rate of 2.6 seconds per rotation, faster than any known asteroid.

The object, known as 2024 BX1, was likely less than one meter wide and entered Earth’s atmosphere on January 21. It disintegrated over Berlin, Germany. Some debris survived the fireball and was retrieved. This is a rare instance of a monitored asteroid fall, where the incoming rock was detected before impact, in this case, just three hours prior to impact.

Maxime Devogele and his team at the European Space Agency’s Near-Earth Object Coordination Center in Italy captured images of the asteroid before impact. Despite traveling at around 50,000 kilometers per hour, the elongated shape of the asteroid made changes in brightness due to rotation quite noticeable in these images.

These changes in brightness corresponded to a rotation time of 2.588 seconds, equivalent to approximately 30,000 rotations per day. “This is the fastest rotation we have observed to date,” Devogele remarked.

Asteroids rotate for various reasons, including early-life collisions. In general, a space rock larger than one kilometer cannot rotate more than once every 2.2 hours, as it would disintegrate. However, smaller asteroids like 2024 BX1 are more resilient and can withstand much faster rotations. “They have internal strength, allowing them to rotate at higher speeds,” Devogele explained.

Measuring the rotation of such objects could be beneficial for planetary defense, providing insights into the durability of small asteroids and their likelihood of surviving passage through Earth’s atmosphere. “If you have hard snow, it will react differently than if you have snow with no internal strength,” Devogele stated.