NASA has collected that elusive, science-fictionish stuff, antimatter, just 20 miles overhead in an experiment carried out three weeks ago. Those familiar with Star Trek will know that antimatter, a substance which carries the opposite charges found in ordinary matter, immediately reacts with matter in a mutual assured destruction reaction that produces massive amounts of energy.
But where to find the real stuff? The US agency carried a Japanese-built five-ton device, slung under a 60-storey-high balloon which remained aloft for 38 hours. It detected several hundred antiprotons among 100 million cosmic ray particles, although the antiprotons could have been produced by ordinary matter-cosmic ray collisions. This left the team with antimatter but also the possibility that it was artificial rather than natural.