📚 Scientists Observe Potentially Hazardous Asteroid Buzz Past Earth With Its Own Moon

Meghan Bartels writes via Space.com: One of Earth's premier instruments for studying nearby asteroids is back to work after being rattled by earthquakes, and its first new observations show that a newly discovered space rock is actually two separate asteroids. The instrument is the planetary radar system at the Arecibo Observatory in Puerto Rico. The observatory was closed for most of January, after a series of earthquakes hit the island beginning on Dec. 28, 2019. The observatory reopened on Jan. 29. Meanwhile, on Jan. 27, scientists using a telescope on Mauna Loa in Hawaii spotted an asteroid that astronomers hadn't seen before. The team dubbed the newfound space rock 2020 BX12 based on a formula recognizing its discovery date. Because of the size of 2020 BX12 and the way its orbit approaches that of Earth, it is designated a potentially hazardous asteroid. However, the space rock has already come as close to Earth as it will during this pass (2.7 million miles or 4.3 million kilometers); astronomers have calculated the asteroid's close approaches with Earth for the next century, and all will be at a greater distance than this one was. [...] Based on the observations, the scientists discovered that 2020 BX12 is a binary asteroid, with a smaller rock orbiting the larger rock. About 15% of larger asteroids turn out, on closer inspection, to be binary, according to NASA. The larger rock is likely at least 540 feet (165 meters) across, and the smaller one is about 230 feet (70 m) wide, according to the observations gathered by Arecibo. When the instrument observed the two space rocks on Feb. 5, they appeared to be separated by about 1,200 feet (360 m).

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