NASA says the space rocks, detected only Sunday, came within a moon's distance of striking the planet's surface.
Two asteroids sped toward Earth but just missed humanity's home planet by what amounts to a cosmic hair's breadth on Wednesday, NASA said.
The asteroids, both measuring several meters in diameter but otherwise unrelated, were passing between the Earth and the moon, according to the space agency. "Neither of these objects has a chance of hitting Earth," NASA said.
One of the asteroids, labeled as 2010 RX30, is roughly 32 to 65 feet in size. It was expected to come within about 154,000 miles of Earth in the early hours. The second, 2010 RF12, is thought to be about 20 to 46 feet in size. It was expected to miss the Earth by just 49,088 miles.
The asteroids were only detected Sunday, by the Catalina Sky Survey just outside Tucson, Ariz., during what NASA referred to as "a routine monitoring of the skies." Their trajectory was then plotted by scientists at the Minor Planet Center, in Cambridge, Mass., who determined that the space rocks would not strike Earth.
The asteroids should have been visible to amateur astronomers using moderate sized telescopes, according to NASA.
While not of the giant, civilization threatening variety of the type depicted in Hollywood blockbusters like "Deep Impact" and "Armageddon", the asteroids, had they made it to the Earth's surface, could have caused at least minor damage, especially if they had struck an urban area.
NASA said similarly sized near-Earth asteroids are an almost daily occurrence, and only strike the planet about once every ten years.