Scientists have discovered that comets are natural sources of antimatter. The announcement was made at April 2002 joint meeting of American Physical Society and American Astronomical Society. ... On July 4, 2005, NASA plans to collide a 350 kilogram spacecraft into the antimatter Comet Tempel 1. The spacecraft's impact with the comet will result in a 15,000 Megatons explosion that will fracture the 125 billion metric ton comet into millions of fragments. The antimatter fragments will disperse into solar orbit and periodically collide with earth for years to come. The antimatter collisions with earth will produce tremendous explosions (equivalent to millions of Megatons of TNT), and will destroy life as we know it. Armageddon will have come. NASA should notify the public of their plans to avoid colliding the spacecraft with the Comet Tempel 1. NASA should also inform the public about the opportunities to use antimatter to benefit humanity and turn the Star Trek Dream into Reality.
(it's amazing what valuable information is on the net, yet nobody really believes it...)