Science: Hazards of the Sun

SOLAR eclipses are one of nature's most fascinating events —and also one of the most dangerous for observers. As more and more of the solar disk is blotted out, the sky darkens, and it becomes easier to gaze directly at the sun. While the visible light lessens, however, the pupils of the viewer's eyes dilate, allowing infra-red radiation from the still uncovered crescent of the sun to focus on his retinas. Although he feels no pain, the infra-red can quickly burn his retinas, causing irreparable damage to his vision. To avoid eye injury, medical authorities suggest that observers who look directly...