Apr 03, 2025 21:00:00

Asteroid '2024 YR4' may hit the moon, say researchers in research paper using state-of-the-art space telescope

At one time, it was feared that the asteroid '2024 YR4' had a non-negligible probability of colliding with the Earth, at about

3% , and if that were to happen, it would cause damage on the ground that would be considered a 'city killer.' However, subsequent tracking confirmed that the probability of it falling to Earth was almost 0%, and monitoringwas discontinued . However, a new paper has been published pointing out that there is still a risk of it colliding with the Moon instead of the Earth.

JWST Observations of Potentially Hazardous Asteroid 2024 YR4 - IOPscience
https://iopscience.iop.org/article/10.3847/2515-5172/adc6f0

'City-Killer' Asteroid Impact Still a Possibility (Just Not With Earth) : ScienceAlert
https://www.sciencealert.com/city-killer-asteroid-impact-still-a-possibility-just-not-with-earth

According to a research team led by Andrew Rivkin, a planetary astronomer at Johns Hopkins University, it is believed that asteroids of a similar size and mass to '2024 YR4' collide with the Earth about once every 5,000 years.

Fortunately, the probability of 2024 YR4 colliding with Earth is virtually zero at 0.001%. However, details such as the exact size and composition of 2024 YR4 are unknown, so it is unclear what type of damage could be expected if an asteroid of the same class as 2024 YR4 were to fall to Earth.

by

European Southern Observatory

To clarify the physical properties of 2024 YR4 and determine what effects such an object would have if it were to collide with another object, the research team used the James Webb Space Telescope (JWST), the most advanced space telescope at the time of writing.

The JWST is equipped with observational instruments such as the Mid-Infrared Research Instrument (MIRI) and the Near-Infrared Camera (NIRCam), which have the precision to capture objects as small as 10 meters in size, enabling more accurate analysis of 2024 YR4, which was previously only a point of light.

Using MIRI observation data and the Near Earth Asteroid Thermal Model (NEATM), the research team was able to narrow down the size of 2024 YR4, which had previously been estimated to be between 40 and 90 meters in diameter, to a range of 60 ± 7 meters in diameter. There is a 92% chance that the asteroid is at least 50 meters in diameter, and it is likely to be 55 to 67 meters in diameter.

The asteroid's albedo , or light reflectance, also suggests that 2024 YR4 may be an 'S-complex asteroid,' which is similar to a rocky S-type asteroid .

Combining these data with the orbital parameters of 2024 YR4, calculations suggest that if 2024 YR4 were to collide with Earth, it would release an energy equivalent to 2-30 megatons of TNT, with an explosion radius of up to 80 kilometers. For comparison, the most powerful nuclear bomb ever tested by the United States had an energy output of only 15 megatons.

'At the time of writing, the possibility of 2024 YR4 impacting the Moon in 2032 has not been ruled out. 2024 YR4 will be in range of the JWST in May 2025 and early 2026, making it an attractive target worth pursuing to see whether it will impact the Moon,' the team wrote in a paper published in Research Notes of the AAS, a journal published by the American Astronomical Society (AAS).