NASA's Radar System Monitors Two Asteroids Approaching Earth
NASA's Jet Propulsion Laboratory (JPL) in Southern California recently monitored two asteroids as they passed close to Earth. One asteroid had a small moon orbiting it, while the other was discovered just 13 days before its nearest approach. These observations, though posing no threat to Earth, are crucial for planetary defense and provide insights into the asteroids' characteristics.
The asteroid 2011 UL21, discovered by the Catalina Sky Survey in 2011, passed Earth on June 27 at a distance of 4.1 million miles (6.6 million kilometers). This is approximately 17 times the distance between the Moon and Earth. Despite being classified as potentially hazardous, future orbit calculations indicate it won't threaten our planet anytime soon.
Asteroid 2011 UL21's Close Approach
Using the Deep Space Network's Goldstone Solar System Radar, JPL scientists transmitted radio waves to 2011 UL21 and received the reflected signals. They found that this nearly mile-wide (1.5-kilometer-wide) asteroid is roughly spherical and has a smaller moonlet orbiting it from about 1.9 miles (3 kilometers) away.
"It is thought that about two-thirds of asteroids of this size are binary systems, and their discovery is particularly important because we can use measurements of their relative positions to estimate their mutual orbits, masses, and densities, which provide key information about how they may have formed," said Lance Benner, principal scientist at JPL who helped lead the observations.
Asteroid 2024 MK's Passage
On June 29, another asteroid named 2024 MK passed within 184,000 miles (295,000 kilometers) of Earth. This distance is slightly more than three-quarters of the distance between the Moon and Earth. The asteroid measures about 500 feet (150 meters) wide and appears elongated with flat and rounded regions.
The team used DSS-14 to transmit radio waves to 2024 MK but received signals using Goldstone's DSS-13 antenna. This "bistatic" radar observation provided detailed images showing concavities, ridges, and boulders about 30 feet (10 meters) wide on its surface.
The close approach of near-Earth objects like 2024 MK happens roughly every few decades. "This was an extraordinary opportunity to investigate the physical properties and obtain detailed images of a near-Earth asteroid," said Benner.
Discovery and Impact
Asteroid 2024 MK was first detected on June 16 by ATLAS at Sutherland Observing Station in South Africa. Earth's gravity altered its orbit during its close pass, shortening its orbital period around the Sun by about 24 days. Although classified as potentially hazardous, future motion calculations show it poses no immediate threat to Earth.
The Goldstone Solar System Radar Group operates under NASA's Near-Earth Object Observations Program within the Planetary Defense Coordination Office in Washington. Managed by JPL, the Deep Space Network receives oversight from NASA Headquarters' Space Communications and Navigation program office within the Space Operations Mission Directorate.
These radar observations not only enhance our understanding of these asteroids but also improve our preparedness for potential future threats from near-Earth objects.
Sign in with Google