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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