Nothing's the Matter With Antimatter, New Experiment Confirms

Many readers shared this report: Antimatter just lost a little more pizazz. Physicists know that for every fundamental particle in nature there is an antiparticle -- an evil twin of identical mass but endowed with equal and opposite characteristics like charge and spin. When these twins meet, they obliterate each other, releasing a flash of energy on contact. In science fiction, antiparticles provide the power for warp drives. Some physicists have speculated that antiparticles are being repelled by gravity or even traveling backward in time. A new experiment at CERN, the European Center for Nuclear Research, brings some of that speculation back down to Earth. In a gravitational field, it turns out, antiparticles fall just like the rest of us. "The bottom line is that there's no free lunch, and we're not going to be able to levitate using antimatter," said Joel Fajans of the University of California, Berkeley. Dr. Fajans was part of an international team known as ALPHA, the Antihydrogen Laser Physics Apparatus collaboration, which is based at CERN and led by Jeffrey Hangst, a particle physicist at Aarhus University in Denmark. Dr. Fajans and his colleagues assembled about 100 hundred anti-atoms of hydrogen and suspended them in a magnetic field. When the field was slowly ramped down, the anti-hydrogen atoms drifted down like maple leaves in October and at the same rate of downward acceleration, or g force, as regular atoms: about 32 feet per second per second. They published their result on Wednesday in the journal Nature. Few physicists were surprised by the result. According to Einstein's theory of general relativity, all forms of matter and energy respond equally to gravity.

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