NASA’s Goldstone planetary radar system recently detected two near-Earth asteroids, 2024 MK and 2011 UL21, flying past our planet. Perhaps a little alarmingly, one was only discovered 13 days ago before safely bypassing Soilbut scientists at NASA Jet Propulsion Laboratory (JPL) in Southern California assure that it never posed a threat. Still, the images they were able to gather have been very informative.
“There was no risk of either object hitting our planet near Earth, but the radar observations made during these two approaches will provide valuable training for planetary defenseas well as information about their size, orbits, rotation, surface details, and clues about their composition and formation,” the team wrote in a press release.
The Goldstone Solar System Radar is located in the desert near Barstow, California. With its 70-meter-long (230-foot-long) fully steerable antenna (DSS-14) — the world’s only fully steerable high-resolution ranging and imaging radar — it provides complete coverage of the sky and has been used to locate objects of interest within the solar system over the past three decades.
During that time it has managed to collect priceless information about other planets, from Mercury Unpleasant Saturnand has supported numerous exploration missions, including the Mars Exploration Rovers, the Cassini Saturn expedition, the Hayabusa asteroid explorers, the SOHO the recovery of the solar observation probe, the Lunar Prospector, and the Venus– studying the Magellan enterprise.
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As seen this week, it has also been used to monitor and study Earth’s proximity. asteroidswhich helps to avoid potential impact hazards and identify targets for future exploration missions. Radar is a powerful tool for studying asteroid properties and orbits: the ground station sends radio waves toward the asteroids and then receives reflected signals back that scientists can use to gather relevant information. If an object’s “echo” is strong enough, radar imaging can achieve a spatial resolution to identify features as fine as 10 meters (32 feet) in size.
Hello asteroids; hello asteroids
On June 27, the radar system tracked the asteroid 2011 UL21 as it flew past Earth at a distance of 4.1 million miles (6.6 million kilometers). As its name suggests, the asteroid is known for NASA scientists since 2011, discovered during the Catalina Sky Survey in Tucson, Arizona.
This object is about 1.6 kilometers (1 mile) wide and was the first to come close enough to be captured by Earth-based radar. This allowed scientists to determine that its shape is roughly spherical and that it is accompanied by its own “moon” orbiting the asteroid at a distance of about 3 kilometers (2 miles).
“About two-thirds of asteroids this size are thought to be binary systems. Their discovery is significant because we can use measurements of their relative positions to estimate their orbits, masses and densities, providing important information about how they might have formed,” said Lance Benner, a principal scientist at JPL who co-led the observations.
NASA scientists say 2011 UL21 is classified as potentially hazardous due to its size, but calculations of the asteroid’s orbit indicate it will not pose a real threat in the near future.
Then, just two days later, another asteroid appeared. The same team observed asteroid 2024 MK passing our planet at a distance of just 184,000 miles (295,000 kilometers), a little over three-quarters of the distance between the moon and Earth. Close approaches like these are relatively rare, the team says, but provide valuable insights that would otherwise be difficult to obtain.
“This was an extraordinary opportunity to investigate the physics of a close-to-Earth asteroid and obtain detailed images,” Benner said.
2024 MK was first identified on June 16 by the Asteroid Terrestrial-impact Last Alert System (ATLAS) at the Sutherland Observing Station in South Africa. “Its orbit was altered by Earth’s gravity as it passed by, shortening its 3.3-year orbital period around the planet the sun “With approximately 24 days,” the team said in the press release.
On June 29, scientists again sent radio waves to 2024 MK, but that timereceived the returning signal using Goldstone’s 114-foot (34-meter) DSS-13 antenna instead of DSS-14. “This ‘bistatic’ radar observation produced a detailed image of the asteroid’s surface, revealing depressions, ridges, and boulders approximately 30 feet (10 meters) wide,” they wrote.
This asteroid is about 150 meters wide and appears elongated and angular, with prominent flat and rounded areas. Although this asteroid is also classified as a potentially hazardous asteroid, calculations of its future motion show that it does not pose a threat to our planet in the near future.