One rotation every 1.63 seconds: The asteroid that entered Earth's atmosphere turned out to be a record holder
An international team led by Chinese scientists has determined that the asteroid 2024 XA1 rotated on its axis once every 1.63 seconds. According to the researchers, this is the shortest rotation period known to date among near-Earth asteroids.
One rotation every 1.63 seconds: An asteroid that entered Earth's atmosphere turned out to be a record breaker
The asteroid 2024 XA1 entered Earth's atmosphere over Eastern Siberia on the morning of December 4, 2024. It had been detected just 10 hours prior, marking the 11th instance where the impact of an asteroid on Earth was successfully predicted in advance.
The study was led by Zhang Xiliang, a researcher at the Yunnan Astronomical Observatory of the Chinese Academy of Sciences, and Fan Xiangyu, a postgraduate student at the same institution. The results were published in The Astronomical Journal.
Only one hour remained for observation
Scientists observed the asteroid during its final hour before atmospheric entry using a 2.4-meter mirror telescope in Lijiang. By recording the changes in the celestial body's brightness, they calculated its rotation period.
As a result, it was revealed that 2024 XA1 rotated around its axis once every 1.63 seconds. The previous record holder — asteroid 2024 BX1 — had a figure of 2.58 seconds.
Why didn't it disintegrate at such speed?
Researchers explained that the centrifugal acceleration generated at such rapid rotation significantly exceeds the gravitational acceleration on the asteroid's surface.
This indicates that 2024 XA1 was not a loose collection of fragments held together primarily by its own gravity, but rather a single solid body. The internal strength of its material prevented it from breaking apart.
Scientists hypothesize that the asteroid may have formed as a result of a collision and fragmentation of a larger celestial body.
Only hours may remain between detecting an asteroid and preparing for it
The small size, faintness, and fast movement of small asteroids make early detection difficult. Additionally, sufficient data must be collected in a short period to assess the energy of a potential impact.
According to the study, in all 13 instances where an asteroid's atmospheric entry was successfully predicted in advance, the objects involved were around a few meters in size. The time between their detection and atmospheric entry ranged from two to 21 hours.
Researchers expect new approaches to help study the physical characteristics of celestial bodies detected on such short notice much faster. This data can be used to assess asteroid threats and improve early warning methods.