Last week, Earth witnessed a rare celestial event with the close passing of two sizable asteroids, named 2024 MK and 2011 UL21.

Although neither posed a threat, both came close enough to be captured by radar imaging systems, providing NASA with valuable snapshots.

These images serve more than just commemorative purposes—they offer scientists crucial insights into the composition and behavior of near-Earth asteroids.

Understanding these properties is essential for developing strategies to mitigate potential future threats from asteroids that may one day approach our planet.

While our solar system’s vicinity around Earth is largely empty, occasional asteroids and comets pass through.

Most pose no danger, but those within a certain proximity or brightness are categorized as potentially hazardous due to the unpredictable nature of orbital dynamics, Science Alert has reported.

Both 2024 MK and 2011 UL21 fell into this category, but fortunately, they remained on safe trajectories during their recent close approaches.

On June 27, 2011 UL21 passed Earth at a distance of 6.6 million kilometers (4.1 million miles), approximately 17 times the Earth-Moon distance.

Just two days later, on June 29, 2024 MK approached much closer, reaching a minimum distance of 295,000 kilometers (184,000 miles)—about three-quarters of the Earth-Moon distance.

Imaging these asteroids, even when relatively close, presents challenges due to their small size and low brightness.

NASA utilizes powerful radar telescopes to transmit radio waves and capture the returning signals, allowing scientists to create detailed images for study.

Written by B.C. Begley