National Geographic : 2001 Dec
astronomy. "From here we can look back 13 billion years to a time when the universe existed simply as plasma-a vast cloud of incandescent gas," says Peterson. Since 1991 the National Science Foundation's Center for Astrophysical Research in Antarctica has built some of the world's most sophisticated infra red, microwave, and radio telescopes at the South Pole. Peterson's Viper radio telescope scans the cosmic background radiation look ing for subtle temperature variations-as small as one one-hundred-thousandth of a degree-caused by the uneven distribution of matter in the first few seconds of the universe. These primeval seeds eventually curdled into vast structures such as stars, planets, galaxies, and clusters of galaxies. Another telescope, AST/RO, probes our own galaxy, looking at how stars form. Still another, DASI, deciphers clues to the size and shape of the universe, how it formed and how it might end. The most bizarre is AMANDA-Antarctic Muon and Neutrino Detector Array-a gigantic telescope that isn't pointed at the sky at all but is aimed instead into the ice in a search for elusive subatomic particles called neutrinos. These mysterious entities-no one is sure if they even have mass-slip through the uni verse like ghosts. Astronomers believe these emissaries from deep space can provide infor mation about the birth of black holes, supernova explosions, and the power sources at the heart of galaxies. But detecting a neutrino is difficult. "They leave no trace," says Darryn Schneider, a physi cist from the University of Wisconsin. "Occa sionally, however, they interact with the polar ice after streaming through the Earth, and when this happens, a particle called a muon is created. Muons give off a blue glow, and this can be used to trace the path of the neutrino." Because muons are also created by cosmic rays in the upper atmosphere, the only way for As if a long run throughguano weren't bad enough, Adelie chicks must pass muster with the parentthey're chasing (top) to be rewarded with a meal of vomit. When adults return from the sea with krill, they make their chicks chase them for as long as 30 minutes before regurgitating. This can help identify and reward the strongest offspring when food is scarce. With no sibling rivalry,a gentoo meal (right) is lessfrenzied.