NASA captures detailed images of passing asteroids, enhancing insights on planetary defence

NASA's Jet Propulsion Laboratory (JPL) in Southern California recently captured detailed images of two asteroids as they passed by Earth. One of these asteroids, discovered just 13 days before its closest approach, revealed a small moon orbiting it. The other asteroid had been previously identified and monitored.

According to Nasa, "There was no risk of either near-Earth object impacting our planet, but the radar observations taken during these two close approaches will provide valuable practice for planetary defense, as well as information about their sizes, orbits, rotation, surface details, and clues as to their composition and formation."

Asteroid 2011 UL21's Characteristics and Discovery

On June 27, asteroid 2011 UL21, discovered by the NASA-funded Catalina Sky Survey in 2011, passed Earth at a safe distance of 4.1 million miles (6.6 million kilometers). This distance is roughly 17 times the gap between the Moon and Earth. Despite being classified as potentially hazardous, calculations indicate that the nearly mile-wide (1.5 kilometers) asteroid poses no threat to Earth in the foreseeable future.

Using the Deep Space Network's 230-foot-wide (70-meter) Goldstone Solar System Radar, scientists transmitted radio waves to the asteroid and found that it is roughly spherical. Additionally, they detected a smaller asteroid, or moonlet, orbiting it from a distance of about 1.9 miles (3 kilometers).


Asteroid 2024 MK's Close Approach
Two days later, on June 29, the team observed asteroid 2024 MK pass Earth at a distance of only 184,000 miles (295,000 kilometers), slightly more than three-quarters of the distance between the Moon and Earth. The asteroid, which measures about 500 feet (150 meters) wide, appears elongated and angular, with prominent flat and rounded regions.

Scientists used the Goldstone Solar System Radar to transmit radio waves to the object and received the signal using a different antenna, resulting in a detailed image of the asteroid's surface. This revealed concavities, ridges, and boulders about 30 feet (10 meters) wide.

Significance of Radar Observations
NASA stated, "There was no risk of either near-Earth object impacting our planet, but the radar observations taken during these two close approaches will provide valuable practice for planetary defense, as well as information about their sizes, orbits, rotation, surface details, and clues as to their composition and formation."

Background on Planetary Defense and Radar Usage
Radar observations play a crucial role in planetary defense by providing detailed information about near-Earth objects (NEOs). These observations help scientists understand the characteristics of asteroids, which is essential for developing strategies to mitigate potential threats. The Goldstone Solar System Radar is a key tool in these efforts, enabling researchers to gather high-resolution data on NEOs' shapes, sizes, and surface features.

(With inputs from TOI)