03/05/2026
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Last year, a near-Earth object measuring approximately 60 meters captured global attention. For a brief period, asteroid 2024 YR4 became the most dangerous asteroid discovered in the last 20 years. While an impact on Earth was soon ruled out, the asteroid disappeared from view with a persistent 4% chance of hitting the Moon on December 22, 2032.
Now, that risk has been eliminated. Astronomers have confirmed that 2024 YR4 will not impact the Moon using new observations made by the Near-Infrared Camera (NIRCam) on the NASA/ESA/CSA James Webb Space Telescope. Instead, it will safely pass by the Moon at a distance of more than 20,000 kilometers.
When asteroid 2024 YR4 drifted away from Earth and disappeared from view last spring, it was widely assumed that it would not be visible again until 2028. But an international team of astronomers identified two narrow opportunities in February 2026 where they believed Webb could detect the faint blob against a sparse background of stars whose positions are well known thanks to the work of ESA’s Gaia mission.
The challenge was significant: use one of the most complex machines ever built by humanity to track a nearly invisible object many millions of kilometers away and then accurately predict its position almost seven years into the future.
Webb was designed to study galaxies and other vast cosmic structures billions of light years away. The telescope’s field of view is very small and detecting one of the faintest asteroids ever targeted within it required extraordinary precision.
The careful planning and analysis of the observations was coordinated through close collaboration between ESA’s Near-Earth Object Coordination Centre, NASA’s Near-Earth Object Studies Center and the Webb mission.
Despite the challenges, the observations were a success. By comparing the position of 2024 YR4 relative to the background stars, the team was able to measure its orbit with enough precision to rule out a lunar impact in 2032.
Decades of engineering, international cooperation and innovation in the fields of science, engineering and planetary defense culminated in the use of humanity’s most powerful robotic space telescope, built by many nations, to detect a distant speck of dust in the void and answer a question of universal importance to all inhabitants of our planet.
The Moon is safe, 2024 YR4 poses no danger, but work continues. ESA’s Space Security Program Planetary Defense team continues to detect and track near-Earth objects to ensure that if a genuine danger ever arises, we will not be surprised.
Learn more about these activities in the links below.
Contact:
ESA Media Relations:
media@esa.int
