An asteroid about 8 meters across passed Earth on Thursday at a relatively close but safe distance, the third such flyby in just two days, U.S. space agency NASA said.

The space rock, called asteroid 2014 EC, came within 62,000 kilometers of Earth's surface at about 4:21 p.m. EDT (2121 GMT), NASA said. That's just 16 percent of the distance between our planet and the moon, which is about 385,000 kilometers on average.

The asteroid, not visible to the unaided eye, was discovered Wednesday by the Catalina Sky Survey in Arizona.

"This is not an unusual event," said Paul Chodas, a senior scientist in the Near-Earth Object Program Office at NASA's Jet Propulsion Laboratory. "Objects of this size pass this close to the Earth several times every year."

The flyby of 2014 EC came closely on the heels of another two space rock encounters. On Wednesday afternoon, a 30-meter-wide asteroid, named 2014 DX110, zoomed by Earth, passing inside the orbit of the moon at a range of 350,000 kilometers.

A third asteroid, 2014 EF, which is closer in size to 2014 EC, passed Earth on Wednesday night, with closest approach about twice as far from Earth as 2014 EC's closest approach.