CAPE CANAVERAL, Fla. - The world is safe -- at least from one asteroid.

A 150-foot cosmic rock hurtled safely past Earth on Friday.

It was the closest known flyby for a rock of its size, passing within 17,000 miles. That's closer than some satellites.

The flyby occurred just hours after a much smaller meteor exploded above Russia's Ural Mountains .

Astronomers say the two events were coincidental, and the objects were traveling in opposite directions. At least one scientist called it an exciting day and "like a shooting gallery here."

The asteroid was invisible to astronomers in the United States at the time of its closest approach on the opposite of the world. But in Australia, astronomers used binoculars and telescopes to watch the point of light speed across the clear night sky.