IT sounded like science fiction NASA scientists using a space probe to chase down a speeding comet 83 million miles away and slamming it into the frozen ball of dirty ice and debris in a mission to learn how the solar system was formed.

A hole was blasted out of the side of a comet today as US scientists showed off their sharp-shooting skills 133 million miles from Earth.

NASA will mark Independence Day in the US with an audacious mission that will blast a stadium- sized hole in a comet half the size of Manhattan.

Nasa’s Deep Impact spacecraft is on course for a July 4 encounter with comet Tempel 1, but mission officials are trying to determine why one of the probe’s telescopes has not focused properly, the space agency said.