Science fiction is rife with tales of high-energy particle annihilation, and indeed, antimatter weapons have appeared in current bestselling novels. These antiparticles are short lived, however, and invariably meet their ordinary-matter match in a destructive process called annihilation.Īnnihilation doesn't mean that the particles completely disappear, it just means that their energy is transferred to a different form, he adds. When ordinary particles are accelerated to very fast velocities and then collide with each other, Coutu explains, antiparticles can be borne out of the ensuing high-energy explosions. Some physicists, instead of observing antimatter produced via nature, study it by making their own in a particle accelerator. This antimatter sprinkle can be a signature for all sorts of particle interactions that occur within our galaxy. He looks for antimatter in the cosmic radiation that rains down upon the earth. To conduct his antimatter research, Coutu sends sophisticated detectors to the edge of the atmosphere on high altitude balloons. We are left today with the resulting matter-dominated universe." So the study of matter-antimatter interactions is a glimpse at the first few moments of a nascent universe. "Right after the Big Bang," Coutu explains, "we believe there must have been exactly the same amounts of matter and antimatter…and yet owing to some small asymmetry in the laws of particle interactions, all of the antimatter and most of the matter in the early universe was annihilated. There was a time when it was as prevalent as matter itself. "Antimatter was not always so rare," Stéphane Coutu, Penn State particle physicist says. Unless you're in the upper atmosphere, or inside a particle accelerator, you're not going to stumble across it. All particles have an antimatter counterpart, even the chargeless neutron (Its constituent quarks do have a charge the antineutron is composed of antiquarks). With antimatter, the mass remains constant, but the sign of the charge is reversed. Every particle in the universe has characteristics such as mass and charge. Antimatter, as the name implies, can be described as the opposite of ordinary matter. Several years pass before American physicist Carl Anderson observes a "positive" electron, or positron that confirms Dirac's prediction.Īlmost 80 years later, positrons and other antiparticles are still studied to try to answer fundamental questions about the universe and the matter it contains.
0 Comments
Leave a Reply. |