Tim Radford
European scientists are to build an antimatter factory at Cern, the European nuclear research laboratory in Geneva.
But even though antimatter would be the perfect fuel – 200 times more efficient than thermonuclear fusion – it may be some time before they have made enough to boldly go with Captain Kirk and Dr Spock. It would take 20kg of antimatter to power the Star Trek starship Enterprise.
Antimatter is puzzling stuff that must have existed in huge quantities at the birth of the universe, but which is destroyed when it brushes against matter.
“Probably 20 kg would be all you would need to power a spaceship and send it round the galaxy,” said Frank Close, of Cern, at the British Association science festival in Cardiff last month.
He admitted there were technical problems. “You have got to put it in the spacecraft and store it in a little vacuum in a magnetic bottle so it doesn’t touch any of the matter the spacecraft is made of, otherwise you blow the end off, then keep it very still so that when the spacecraft takes off the antimatter goes with it without the slightest jiggle. And you have to put it there without blowing yourself up. These are technical problems that will be solved,” he said.
The antiparticles made in Europe and the United States in the last 20 years add up to less than a millionth of a gram. The antimatter factory would make 2 000 atoms of anti-hydrogen an hour. It would take 10 000 times longer than all history to make 20kg.
Doctors already use tiny particles of antimatter in a scanning technique called positron emission tomography. But three-quarters of the universe is composed of hydrogen which condensed out of the Big Bang in the first instant of time. The latest theories say equal quantities of antimatter should have been created, too. So somewhere there should be enough anti-hydrogen to fill an anti-universe. If there is not, why not? Close asked. Scientists will make the stuff, cool it to very low temperatures and examine it to answer questions about the nature of matter itself, and the laws that govern the universe.
The simplest form of antimatter to handle in bulk would not be anti- hydrogen but anti-water, or better still, anti-ice. “So if you have a good way of making not just anti-hydrogen but anti-oxygen and bringing them together to make anti-water and freezing it to make anti-ice, talk to me,” Close said.