By comparing distant primeval galaxies with older ones nearby, astronomers hope to determine how galaxies form and evolve. Searching for that answer, physicists are groping toward a theory of quantum gravity. Today a frozen world, Mars at one time may have had more temperate conditions, with flowing rivers, thawing seas, melting glaciers and, perhaps, abundant life. Recently discovered microorganisms that dwell within the Earth's crust could reveal clues to the origin of life. Electrical impulses from nerves and muscles can command computers directly, a method that aids people with physical disabilities.
Astronomers stand at the gateway to worlds beyond our own.
Recent experiments exploiting subtle quantum effects yield important clues about why some ceramics conduct electricity without resistance. Two relativists present their distinctive views on the universe, its evolution and the impact of quantum theory. The International Space Station will be the most expensive object ever built. Although many scientists oppose this grandiose scheme, its political momentum now appears unstoppable. Studies of the mountain's history and geology can contribute useful insights but not unequivocal conclusions.