The label " space rock " feels like an understatement for what NASA just observed.

A rock is something you throw at a window to get someone's attention. A rock holds down your picnic blanket to keep it from flapping in the wind. This rock, at 660 feet wide, spans two American football fields — and then some.

The asteroid , called 1997 QK1, made its nearest approach in space on Aug. 20 at 1.9 million miles away from Earth. The ancient rubble hasn't come this close to the planet in more than 350 years.

The flyby gave astronomers a chance to inspect its size, rotation, surface, and shape. Before taking these images with the Deep Space Network's Goldstone Solar System Radar , shown below, scientists knew hardly anything about it. Now it's less of a stranger.

"The astero

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