Earth's new moon is a mini marvel the size of a car

摘要

OUR planet might have a tiny new moon. It is probably between 1.9 and 3.5 metres across, about the size of a car, making it no match for Earth's main satellite. It circles our planet about once every W7 days on a wide, oval-shaped orbit, mostly far outside the larger moon's path. On 19 February, astronomers at the Catalina Sky Survey in Arizona spotted the newcomer as a dim object moving quickly. Over the next few days, researchers at six more observatories around the world watched the object, designated 2020 CD3, and calculated its orbit, confirming that it has been gravitationally bound to Earth for about three years.