NASA’s James Webb Space Telescope recorded its initial detailed images of asteroid 2024 YR4, which used to be Earth’s closest asteroid threat. The ATLAS system discovered asteroid 2024 YR4 in Chile during late December 2024, which became a headline story when scientists initially estimated a 3.1% possibility of Earth collision in 2032, making it the top entry on NASA’s Sentry Impact Risk Table.
The February measurements reduced the impact risk to an almost nonexistent level. Scientists continue to study 2024 YR4 because it maintains the potential to strike the Moon during December 2032. The Moon impact probability increased from 1.7% to 3.8%, which led to ongoing observations of the object.
The advanced infrared capabilities of the Webb Space Telescope measured the asteroid at 174 to 220 feet, which equals the height of a 10-story building. Prior observations from ground-based telescopes indicated that YR4 could measure anywhere from 131 to 295 feet in length. The data gathered by Webb confirms that YR4 represents the tiniest object detected by the operational telescope with the highest power capabilities.
Scientists utilize YR4 as a research example to enhance asteroid detection methods and tracking protocols and emergency response plans for potential future threats to Earth. Astronomer Andrew Rivkin from Johns Hopkins University described the observations as “invaluable” because they revealed characteristics of future Earth-approaching objects.
NASA and ESA will track 2024 YR4 one more time during late April or early May when it becomes undetectable through their instruments. The analysis of YR4 alongside Apophis supports planetary defense research to maintain space agency preparedness against potential Earth or lunar impact threats.
