Good News! The Subaru Telescope Confirms that Asteroid 2024 YR4 Will Not Hit Earth.

On December 27th, 2024, the Chilean station of the Asteroid Terrestrial-impact Last Alert System (ATLAS) detected 2024 YR₄. This Near-Earth Asteroid (NEA) belongs to the Apollo group, which orbits the Sun with a period of approximately four years. For most of its orbit, 2024 YR4 orbits far from Earth, but sometimes, it crosses Earth’s orbit. The asteroid was spotted shortly after it made a close approach to Earth on Christmas Day 2024 and is now moving away. Additional observations determined it had a 1% probability of hitting Earth when it makes its next close pass in December 2032.

This led the International Asteroid Warning Network (IAWN) – overseen by the United Nations Office for Outer Space Affairs (UNOOSA) – to issue the first-ever official impact risk notification for 2024 YR₄. The possibility of an impact also prompted several major telescopes to gather additional data on the asteroid. This included the Subaru Telescope at the Mauna Kea Observatory in Hawaii, which captured images of the asteroid on February 20th, 2025. Thanks to the updated positional data from these observations, astronomers have refined the asteroid’s orbit and determined that it will not hit Earth.

This is not the first time the odds of the asteroid hitting Earth have been reevaluated. Throughout February, refined measurements of the asteroid altered the estimated likelihood multiple times, first to 2.3% and then to 3.1%, before dropping significantly to 0.28%. Thanks to the observations of the Subaru Telescope, which were conducted at the request of the JAXA Planetary Defense Team and in response to the IAWN’s call for improved orbital tracking, the chance of impact has been downgraded to 0.004%.

The updated estimate was calculated by NASA’s Center for NEO Studies (CNEOS), the ESA’s Near-Earth Objects Coordination Centre (NEOCC), and the NEO Dynamic Site (NEODyS). The Subaru observations were conducted using the telescope’s Hyper Suprime-Cam (HSC), a wide-field prime-focus camera that captured images of 2024 YR₄ as it grew dimmer. The observations have since been forwarded to the Minor Planet Center (MPC) of the International Astronomical Union (IAU). Dr. Tsuyoshi Terai of the National Astronomical Observatory of Japan (NAOJ), who led the observations, explained:

“Although 2024 YR₄ appeared relatively bright at the time of its discovery, it has been steadily fading as it moves away from the Earth. By late February, observations would have been extremely challenging without a large telescope. This mission was successfully accomplished thanks to the Subaru Telescope’s powerful light-gathering capability and HSC’s high imaging performance.”

Based on these latest observations, the IAWN reports that 2020 YR₄ will “pass at a distance beyond the geosynchronous satellites and possibly beyond the Moon.” They also indicate that there is no significant potential that the asteroid will impact Earth in the next century. The IAWN also states that it will continue to track 2024 YR4 through early April. At this point, it will be too faint to image and won’t be observable from Earth again until 2028.

Further Reading: NAOJ

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