A big scary-sounding asteroid is no longer even a remote threat to smash into Earth in about 20 years, NASA says.

A Nasa spacecraft flew through the bright halo of a distant comet to scoop up less than a thimbleful dust that could shed light on how our solar system was formed.

A Nasa spacecraft flew through the bright halo of a distant comet today to scoop up less than a thimbleful of dust that could shed light on how our solar system was formed.

US astronomers are keeping close watch on a newly discovered 2km-wide asteroid but do not expect it to collide with Earth.