A small asteroid designated 2017 UJ2 flew past Earth at a very close distance of 0.05 LD or 0.00012 AU (~17 951 km / 11 154 miles) from the center Earth on October 20, 2017, one day before it was discovered. This is the 40th known asteroid to flyby Earth within 1 lunar distance since the start of the year, and the second closest.
2017 UJ2 belongs to the Apollo group of asteroids. It has an estimated diameter between 1.9 and 4.1 m (6 and 13 feet) and it flew past Earth at a speed (relative to the Earth) of 8.48 km/s at 14:07 UTC on October 20.
It was first observed at Catalina Sky Survey on October 21, 2017, one day after its close approach.
This is the 40th known asteroid to flyby Earth within 1 lunar distance since the start of the year, and the second closest. The only known asteroid to flyby us closer than 2017 UJ2 this year is 2017 GM. This one flew past us at 0.04 LD / 0.00011 AU (~16 455 km / 10 225 miles) from the center of Earth on April 4, 2017.