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
Volume 278, Issue 2
You are currently logged out. Please sign in to download the issue PDF.
Features
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
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