A massive asteroid has safely passed Earth in the closest known flyby ever for a rock that large.
The U.S. space agency, NASA, said the more than 45-meter asteroid passed within 28,000 kilometers of the planet on Friday -- closer than some satellites.
The asteroid passed Earth just hours after a much smaller meteor exploded in the sky above Russia's Ural Mountains.
NASA scientists warned last week about the asteroid, but said there was no chance the space rock would hit Earth.
The speeding asteroid was too small to be seen with the naked eye as it passed overhead. But astronomers in Australia were able to watch the point of light speed across the sky through binoculars and telescopes.
The asteroid was expected to move eight times as fast as a rifle bullet.
NASA says this is one of the largest asteroids ever to fly by Earth, but other, much larger space rocks crashed into Earth's surface millions of years ago, causing calamitous damage.
The last asteroid to cause serious destruction on the ground exploded over a Siberian forest in 1908.