LIVE: Asteroid 2012 DA14 set for record Earth pass
15 February 2013 Last updated at 18:47 GMT
An asteroid as large as an Olympic swimming pool will race past the Earth on Friday at a distance of just 27,700km (17,200mi) - the closest ever predicted for an object of that size.
It will pass closer even than the geosynchronous satellites that orbit the Earth, with its closest approach predicted to be at 19:25 GMT.
Coverage courtesy of Nasa