Close Asteroid Encounter
Asteroid 2010 WC9 safely passed at about half’s the moon’s distance on Tuesday, May 15, 2018. It reached its minimum distance from Earth at 22:05 UTC (5:05 p.m. CDT).
Estimates of its size range from 197 to 427 feet (60-130 meters), making the May 15 pass one of the closest approaches ever observed of an asteroid of this size.
At the time of minimum distance, the asteroid will be 0.53 lunar-distances from Earth (126,419 miles or 203,453 km from Earth). According to orbit calculations made by NASA’s Jet Propulsion Laboratory, the May 15 close approach is the closest of this particular asteroid in nearly 300 years.
Asteroid 2010 WC9 was “lost” and then found again. The Catalina Sky Survey in Arizona first detected it on November 30, 2010, and astronomers watched it until December 10, when it became too faint to see. They didn’t have enough observations to track its orbit fully and so predict its return. On May 8, 2018 – almost eight years later – astronomers discovered an asteroid and gave it the temporary designation ZJ99C60.
Then they realized it was asteroid 2010 WC9, returning. Asteroid 2010 WC9 is an Apollo type space rock. At no time will it be visible to the eye as it sweeps past Earth, moving at a speed of 28,655 miles per hour (46,116 km/h). There is no danger of a collision during the May 15, 2018 encounter.