Nasa is celebrating 50 years of space exploration by beaming a track by The Beatles into space.

Across The Universe, written by Lennon and McCartney in 1969, will be aimed at the North Star, 431 light years away from Earth.

The track will be sent over the Deep Space Network at midnight GMT on 4 February, and Nasa is asking fans to play the track at the same time.

"I see this as the beginning of the new age in which we will communicate with billions of planets across the universe," said John Lennon's widow Yoko Ono.

The song, which contains the line 'Nothing's gonna change my world', was included on Let It Be, the final original album by The Beatles.

Sir Paul McCartney welcomed the transmission. "Amazing! Well done Nasa!" he said in a message to the space agency. "Send my love to the aliens. All the best, Paul."

McCartney has a long association with Nasa, and played a concert in 2005 for astronauts on the International Space Station.

The sending of The Beatles' track forms part of celebrations of the launch of Explorer 1, the first US satellite, and the founding 45 years ago of the Deep Space Network, an international network of antennas that supports missions to explore the universe.