By Steve Connor, Science Editor
09 June 2005
Scientists are preparing to shoot a comet with a self-guided copper missile travelling at 100 times the speed of a bullet.
The explosive encounter is set for 4 July - Independence Day in America- and it will be observed by astronomers around the world who hope it will shed light on the origin of the planets.
By firing a relatively large object into the icy interior of a comet, scientists hope to dig out and analyse the primordial material that was around when the solar system formed more than four billion years ago.
It has taken six months for the £140m Deep Impact probe to travel the 268 million miles from Earth to comet Tempel 1. It will take a further 24 hours for its missile to make the final trip from mother craft to the impact site. Comet Tempel 1 is nearly nine miles long and 2.5 miles wide and scientists insistits course around the Sun will remain unaltered in the collision with the half-ton bullet.
http://news.independent.co.uk/world/science_technology/story.jsp?story=645333