http://www.foxnews.com/story/0,2933,63446,00.html
European scientists say they have created enough antihydrogen -- a type of the mirror-image, antimatter stuff that fictionally powers spaceships on Star Trek -- to test a widely held basic model of the universe. While antihydrogen has been made before, the more than 50,000 atoms created at the CERN particle accelerator in Geneva are "by far, the most produced," said Jeffrey Hangst, a leader of the ATHENA collaboration, one of two groups of physicists working on antihydrogen at CERN. The quest to understand and manipulate antimatter is one of the most competitive and esoteric pursuits in science. Not all particle physicists -- even within CERN -- agree with the new finding. A spokesman for the competing ATRAP Collaboration at CERN said he doubts that antihydrogen had been produced in the latest experiment. The ATHENA group relied on indications of the simultaneous destruction of antihydrogen's two atomic particles -- the positron and the antiproton -- to show it had been produced, said Harvard physicist Gerald Gabrielse, spokesman for the ATRAP group. "Our long experience with these very difficult experiments warns that observing simultaneous positron and antiproton annihilation does not ensure that antihydrogen has really been produced," Gabrielse said. ATHENA researchers, whose work appears in Thursday's issue of the journal Nature, plan to make more antihydrogen to test the Standard Model, equations that explain the nature of matter and energy. If the antihydrogen doesn't behave the same as normal hydrogen "the textbooks would have to be rewritten," said Hangst, who is a physicist at the University of Aarhus in Denmark, along with his CERN work. "It would imply that we have overlooked something fundamental about how nature works," Hangst said. "Such a discovery certainly wouldn't help you to build a better computer or TV, but it might shed some light on why we have a universe that looks the way it does." Antimatter is the mirror image of conventional matter with opposite properties. Antimatter is destroyed whenever it collides with matter, turning both into bursts of electromagnetic radiation. Scientists believe this process was crucial to the fiery creation of the universe billions of years ago. Why so little antimatter is made now in nature remains one of physics' great dilemmas. Only modest levels have been detected in cosmic ray showers and the nuclei of distant galaxies. Antimatter is difficult to make in the lab, too. Giant particle accelerators at CERN and Fermilab near Chicago specialize in the quest. In the first antimatter experiments a few years ago, only dozens of short-lived antimatter particles were created. Hydrogen, the most abundant element, consists of an electron orbiting a proton. Antihydrogen is the exact opposite; a positron -- an electron with a positive charge -- orbiting an antiproton, or a proton with a negative charge. In the latest experiments, ATHENA researchers used the CERN accelerator to create antiprotons and electromagnetically trapped them in a vacuum chamber. A radioactive source, meanwhile, was used to create positrons, which were held in a separate trap. The antiprotons were then fed into the pool of positrons, where the two combined to form antihydrogen. The antimatter was short-lived; Hangst said it was annihilated when it bumped into normal matter. Detectors picked up the unique signatures of antimatter as it was destroyed, he said. David Christian of Fermilab said the ATHENA group appears to have made antimatter in greater quantities. "They've got a lot more big steps they need to make, but this one is a big step," Christian said. However, Gabrielse said upcoming publications by his group "will show how it is possible to be fooled." "Our initial understanding of the recent report makes it likely that we will present the case that the reported observations do not prove that any antihydrogen was observed," he said. ATHENA researchers plan several experiments to test the Standard Model by creating more antihydrogen, exciting it with lasers and observing what happens when the atom's positron jumps from one orbit to another. They also want to study gravity's effect on antihydrogen. Some speculate antimatter "falls up," but most scientists don't believe that is the case, Hangst said. Using antimatter to power a starship or create a weapon, meanwhile, is still in the realm of science fiction, he said. Making antiprotons requires 10 billion times more energy than it produces. For example, the antimatter produced each year at CERN could power a 100 watt light bulb for 15 minutes, Hangst said. xponent Explodio Maru rob _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
