A small asteroid will pass closer to Earth next week than the TV satellites that ring the planet, but there is no chance of an impact, Nasa has said.
The celestial visitor, known as 2012 DA14, was discovered last year by a group of amateur astronomers in Spain. The asteroid is about the size of an Olympic swimming pool at 46 metres in diameter and is projected to come as close as 27,520km from Earth during its approach on February 15.
That would make it the closest encounter since scientists began routinely monitoring asteroids about 15 years ago.
Television, weather and communications satellites fly about 500 miles (800km) higher. The moon is 14 times farther away.
Even so, "no Earth impact is possible", the astronomer Donald Yeomans, with Nasa's Jet Propulsion Laboratory in Pasadena, California, told reporters during a conference call.
The time of the asteroid's closest approach will be 7.24pm GMT (2.24pm EST) - daylight in the US but dark in Europe, Asia and Australia, where professional and amateur astronomers will be standing by with telescopes and binoculars to catch a view.
DA14 will soar through the sky at about 13km a second. At that speed, an object of similar size on a collision course with Earth would strike with the force of about 2.4m tonnes of dynamite. The last time that happened was in 1908 when an asteroid or comet exploded over Siberia, levelling 80m trees over 830 square miles (2,150 sq km).