Antimatter atoms trapped: now to actually study them

Antimatter atoms have been trapped for the first time by physicists at Cern, home of the Large Hadron Collider. The researchers have reported in Nature that they had managed to trap 38 atoms of antihydrogen in a magnetic container for one sixth of a second before they were annihilated.

However, there is a long way to go before antimatter can be used - as in the sci-fi series Star Trek - as a source of power for a starship. The Cern experiment has the more humble aim of actually producing enough antimatter to study.

Scientists theorise that at the moment of the Big Bang, the universe consisted of equal quantities of matter and antimatter. Matter and its counterpart are identical except for opposite charge. One of the great unanswered questions of particle physicists is why the visible universe today consists almost entirely of ordinary matter.

Scientists have isolated antimatter particles before - and have even bound together a positron and antiproton (the antimatter versions of an electron and proton) to make antihydrogen (pictured above). However, studying antimatter has been a tricky prospect, because it is obliterated if it comes into contact with normal matter.

Researchers use a magnetic container to hold the particles when they are produced, but they are usually so highly energetic that they hit the container wall and cease to exist.

Cern scientists have now succeeded in creating 'cold' antimatter particles with relatively little energy, which makes them easier to 'handle' in a magnetic container.

They proved that of the millions of antiproton and positron particles they produced in their experiments, 38 antihydrogen atoms formed, each for around a sixth of a second.

Cern spokesman Jeffrey Hangst told AP: "For us it's a big breakthrough because it means we can take the next step, which is to try to compare matter and antimatter."

Future experiments will attempt to trap more antihydrogen atoms for longer periods so that they can be studied in greater depth to see if antimatter really does behave in the same way as matter. ·