Nasa plans big bang for comet

Scientists at Nasa are preparing for what they hope will be a carefully controlled big bang in space.

The space agency said it hopes to launch a rocket from Cape Canaveral to intercept the Tempel 1 comet as it travels just beyond the orbit of Mars, about 206 million kilometres from Earth.

The pyrotechnics from the 37,000km/h crash should occur on July 4, Independence Day in the US.

Researchers hope that the deliberate smash will reveal the secrets of what lies within the cores of comets. The explosion, equivalent to igniting 4.5 tonnes of TNT in space, will send a shower of material into space that will be viewed and analysed on Earth.