Science: Sky Spectacular

Few areas of North America are more isolated or serene than Mexico's Oaxaca state, astride the Isthmus of Tehuantepec. Foreign visitors are few, and they are usually young Americans interested in eating local "magic" mushrooms. Yet for the past few weeks, Oaxaca (pronounced wa-hac-a) has been bustling with unnatural activity. Toting tons of expensive paraphernalia, nearly 800 scientists from 14 countries have descended on the mountainous state. Frightened by the "demon" that the scientists have come to see, superstitious Indian villagers have been busily offering prayers, lighting candles and staging other rituals. Their supplications are designed to keep the demon at a distance. But they are not likely to succeed. On the morning of Saturday, March 7, the sun will temporarily vanish from the skies of Oaxaca, blotted out by a total solar eclipse.

Oaxaca lies directly in the path of the narrow, 100-mile-wide shadow that will be cast by the moon as it moves directly between earth and sun. If the usual cloud-free weather prevails, the remote area will offer astronomers a ringside seat for the sky spectacular. As the moon's shadow sweeps northward, millions of Americans and Canadians may also be able to catch a glimpse of a total or nearly-total eclipse, although direct observation can be highly dangerous (see box). The path of totality extends across the Gulf of Mexico, cuts through Florida, Georgia and the Carolinas, brushes past Virginia and New England, and finally disappears at sea beyond Newfoundland and Labrador. Viewers as far away as San Francisco may have an opportunity to see part of what some overly exuberant sky watchers have already dubbed "the eclipse of the century."

Perverse Habit. Actually, solar eclipses are fairly common. As many as five can occur in a single year, although they invariably last no more than a few minutes and often frustrate astronomers by what Veteran Eclipse Watcher Donald H. Menzel of Harvard calls their "perverse habit of hitting desolate regions." Because of its favorable viewing path and timing—near the peak of the sun's eleven-year sunspot cycle—the March 7 eclipse is being eagerly awaited by astronomers.

Millions of dollars have been spent on preparations for what may well be the most intensely observed eclipse in history. Besides the numerous telescopes, cameras and other elaborate gear located in Oaxaca, other equipment is being set up at observatories all along the Eastern Seaboard. By the fortunes of celestial mechanics, the eclipse's path will cross Wallop's Island, Va., where NASA scientists will send up 33 probing rockets as the shadow approaches. In addition, several research planes will seek an above-the-weather look at the eclipse; a U.S. Air Force KC-135 will even race the moon's shadow in order to get a few precious extra moments of observation time.