Washington - The US space agency has released a rare photo of the Earth and moon taken from the vantage point of the outer solar system, with Saturn's rings in the shot.The colour images were taken by Nasa's Cassini spacecraft at a distance of nearly 1.4 billion km away, Nasa said.After calling on Earthlings to wave at Cassini for the picture last week, NASA said the chance to "photobomb" another planet drew 20,000 participants, even though the Earth appears as just a tiny speck in the final image."The July 19 Earth-imaging event marked the first time Earthlings had advance notice that their portrait was being taken from interplanetary distances," Nasa said."It was the also the first time Cassini's highest resolution camera captured the Earth and its Moon as two distinct objects."The unusual angle was possible because the Sun had moved behind Saturn from the spacecraft's point of view, blocking out most of the light that would otherwise have damaged the camera's detectors."We may not be able to see individual continents or people in this portrait of Earth, but this pale blue dot is a succinct summary of who we were on 19 July," said Linda Spilker, Cassini project scientist, based at Nasa's Jet Propulsion Laboratory. "Cassini's picture reminds us how tiny our home planet is in the vastness of space."