A rogue asteroid shaped like a wading hippo has just skimmed past Earth.

The space rock, which measures a mile long, was 'potentially hazardous', according to NASA.

The close flyby saw the object – dubbed 2003 SD220 – whizz within 1.8 million miles of Earth, or about seven times the distance between Earth and the Moon.

Nasa researchers took radar readings of the space rock, comparing its shape to the 'exposed portion of a hippopotamus wading in a river.'

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This was its closest approach in over four centuries, and the object will not come this close again for 52 years, scientists said.

Images revealed the rock rotates once every 12 days and has a complex spin similar to a poorly thrown American football.

The asteroid, first discovered in 2003, is classified as "potentially hazardous" due to its size and close approaches to Earth's orbit.

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However, the latest radar measurements confirm it does not pose a future impact threat to Earth.

Scans were taken by coordinating Nasa's 70m antenna in California, the National Science Foundation's 100m telescope in West Virginia and the Arecibo Observatory's 305m antenna in Puerto Rico.

'The radar images achieve an unprecedented level of detail and are comparable to those obtained from a spacecraft flyby,' said observation lead scientist Lance Benner of the Nasa Jet Propulsion Laboratory in Pasadena, California.

Click here to read more from The Sun, where this story was originally published.