In March 2026, what celestial body's potential impact by asteroid 2024 YR4 in 2032 was ruled out by NASA's James Webb Space Telescope observations?

In March 2026, astronomers made a significant update regarding asteroid 2024 YR4, ruling out its potential impact on the Moon in 2032. This asteroid, discovered in late 2024, initially garnered attention due to a small but notable chance of impacting Earth in December 2032, a possibility that was later dismissed with further observations. However, a lingering 4.3% chance of a lunar collision on December 22, 2032, remained, keeping scientists vigilant.

The crucial breakthrough came from NASA's James Webb Space Telescope (Deals) (JWST) observations, collected in February 2026. These observations, among the faintest ever made of an asteroid, allowed experts at NASA's Center for Near-Earth Object Studies to significantly refine the asteroid's trajectory. The refined data conclusively showed that 2024 YR4 would safely pass the Moon at a distance of approximately 13,200 miles (21,200 kilometers), eliminating any risk of impact.

The James Webb Space Telescope's unique capabilities were vital for this assessment. Since spring 2025, asteroid 2024 YR4 had been too faint to be observed by other Earth-based or space-based telescopes. The JWST's extreme sensitivity and precise moving-target tracking allowed it to capture the necessary data, demonstrating its critical role in planetary defense efforts. This roughly 200-foot-wide asteroid, once considered the most dangerous discovered in two decades, will now be a harmless visitor in our celestial neighborhood.