June 6, 2011

Scientists theorize that at the time of the Big Bang, nearly 14 billion years ago, matter and antimatter probably existed in equal quantities. For reasons scientists have yet to figure out, nature developed in a way that it preferred matter, so today our universe is made up mostly of matter, and antimatter has become extremely rare. One of physics' biggest questions is whether matter and antimatter in our observable universe really are asymmetric. We assume that the world is made up of symmetries, but maybe we have to think again. The scientific history of antimatter goes back quite some time, too: Scientists were aware of its existence at the beginning of the previous century, and they managed to prove its existence in the 1930s. Since then, it has been one of physics' big unsolved mysteries, and researchers have been trying to reproduce antimatter to analyze it further. By doing so, they hope to find out if there are places that are almost entirely antimatter, and what would happen on our planet if we could harness it. Scientists at the European Organization for Nuclear Research (CERN) in Switzerland have managed to store anti-hydrogen atoms which they had trapped for 16 minutes. This, they hope, will bring them closer to solving the mysteries of antimatter. While it is not a scientific breakthrough because it always has been known to be possible, albeit very difficult, it certainly is an experimental breakthrough. Normally, particles and anti-particles annihilate each other with a lightning flash when they collide. The team who conducted the experiment at CERN managed to create what the experimenters refers to as a “soft landing” of particles and anti-particles so they didn't annihilate each other. In the study, published in the journal Nature Physics, the researchers report trapping some 300 anti-atoms. Last fall, the researchers managed to trap dozens of antimatter atoms and keep them for less than a second. Nobody had ever achieved this before, but it was not enough to conduct thorough experiments. Using laser and microwave spectroscopy, the research team hopes to be able to compare the particles to their hydrogen counterparts. They can keep the anti-hydrogen atoms trapped for 1,000 seconds, the longest ever, which is long enough to begin to study them, even with the small number that they can catch so far. It will be the first time anybody has interacted with anti-atoms to probe their structure. The researchers will look for discrepancies in something called the charge-parity-time reversal (CPT) symmetry. CPT means that a particle moving forward through time in our universe should be indistinguishable from an antiparticle moving backwards through time in a mirror universe. They have started conducting measurements and want to present first results by the end of the year.