The Viking Longship

Long, narrow ships packed with warriors helped to make the Vikings the dominant power in Europe for three centuries, beginning in about A.D. 800

The Origin of Birds and Their Flight

Anatomical and aerodynamic analyses of fossils and living birds show that birds evolved from small, predatory dinosaurs that lived on the ground

Scientists in Black

The Theory Formerly Known as Strings

The Theory of Everything is emerging as one in which not only strings but also membranes and black holes play a role

The Search for Blood Substitutes

The threat of global shortages of blood and fears about contamination have hastened attempts to find life-sustaining alternatives. Several of these compounds look promising

Greenland Ice Cores: Frozen in Time

Ice, frozen in place for tens of thousands of years, provides scientists with clues to past—and future—climate

Everyday Exposure to Toxic Pollutants

Environmental regulations have improved the quality of outdoor air. But problems that persist indoors have received too little attention