Scientific American Magazine

Each spring for the past decade the ozone layer in the atmosphere has thinned at the South Pole. Is the loss an anomaly, or is it a sign that the ultraviolet-absorbing layer is in jeopardy globally?

These immune-system cells recognize a target, close in on it and bind tightly to it. Then they secrete onto its surface a lethal pore-forming protein that causes the target cell to leak and die

Einstein held that quantum-mechanical descriptions of physical systems are incomplete. Laboratory tests show he was probably wrong; the bizarre nature of the quantum world must be accepted

An array of 10 radio antennas across the U.S. will provide the most detailed images yet of the universe. With it astronomers will explore such cosmic puzzles as the mysterious processes powering the quasars

Fishes that live between the tides are alternately buffeted by waves and isolated in pools and on mud flats. Anatomy, physiology and behavior suit them to their rigorous habitat

The rare-earth elements, on which electronic, metallurgical and glass industries depend, are not all that scarce in minerals. The elemental abundances reveal the geochemistry that leads to a mineral's formation

Form, color and spatial information are processed along three independent pathways in the brain. That explains why certain images can create surprising visual effects

Just a century ago this inconspicuous device made the distribution of electric power a practical endeavor. Many elements of modern life depend on it, yet it remains one of technology's unsung heroes