NASA Discovers Moon Orbiting 'Planet Killer' Asteroid During Close Flyby

Recent radar imaging reveals a previously unknown moonlet orbiting the massive asteroid 2011 UL21, enhancing planetary defense research.

Asteroid 2011 UL21, a mile-wide 'planet killer,' passed Earth at its closest point in over a century.
NASA's Goldstone radar captured images showing a small moon orbiting the asteroid.
The discovery adds to the understanding of binary asteroid systems, which are common among large asteroids.
The asteroid's approach provided valuable data for future planetary defense strategies.
A second asteroid, 2024 MK, also passed close to Earth, with its trajectory altered by the encounter.