SCIENCE

A glimpse of heaven

The sun’s corona blazed in a darkened sky

DIANE BRADY July 22 1991
SCIENCE

A glimpse of heaven

The sun’s corona blazed in a darkened sky

DIANE BRADY July 22 1991

A glimpse of heaven

SCIENCE

The sun’s corona blazed in a darkened sky

It was an event so rare in nature that some scientists and curious laymen travelled thousands of miles to points along Mexico’s Baja peninsula to watch. Others viewed last week’s eclipse of the sun in Hawaii after arriving by aircraft or aboard luxury cruise ships. Altogether, millions of people, including at least 200,000 visitors from scores of countries, watched from Hawaii to Brazil as the longest and most spectacular solar eclipse of the century briefly plunged some parts of the world into darkness on July 11. “It was so incredibly eerie and spectacular,” said Michael Watson, a Toronto lawyer and amateur astronomer who led 155 members of the Royal Astronomical Society of Canada to Baja for the eclipse. “I have never seen anything like it.”

During a period in which the eclipse was visible in the best viewing locations for a maximum of six minutes and 54 seconds, the moon passed between the Earth and the sun, causing the shadow of the moon to blot out the sun’s light. In an area stretching from Hawaii through Baja and over mainland Mexico, south through Latin America and Brazil, darkness descended. In some areas on the path of the

eclipse, birds grew silent and animals acted as though night had fallen. It was the longest total eclipse of the sun since 1973; there will not be another to equal it until the year 2132. In most parts of the United States and Canada, the event that some enthusiasts called “the eclipse of the millennium” was seen as partial: typically, in the cloudy sky over Vancouver, only 15 per cent of the sun was obscured.

Working from one of the locations where the eclipse could be seen most completely, scientists at Hawaii’s Mauna Kea observatory trained seven telescopes and dozens of cameras on the sun in the hope of gathering scientific data that may answer fundamental questions about the sun’s chemistry. Said David Naylor, a professor of physics at Alberta’s University of Lethbridge and one of two Canadian scientists who

2 saw the eclipse from Mauna Kea: “It was an absolute miracle that the path of the eclipse passed right overhead of the best observing site on Earth.” For those standing directly beneath the umbra, or dark inner part, of the moon’s shadow, the sun’s corona, or outer atmosphere, blazed in a darkened sky. Added Naylor: “This is a once-in-three-life-

times phenomenon.” But in the end, scientists said, the less-than-perfect weather conditions somewhat obscured the eclipse.

Scientists said that few events in nature surpass the eerie effect of a total solar eclipse. About once every 16 months, the moon briefly passes between the sun and the Earth, blocking the sun’s rays. But such eclipses last only seconds and are visible only on some parts of the Earth’s surface. What made last week’s eclipse uncommon was that the moon was exceptionally close to the Earth and the Earth was at its farthest annual point from the sun. As a result, the eclipse was visible for an unusually long time. Solar eclipses have inspired awe and terror since the dawn of civilization. Indeed, the word eclipse is derived from the Greek word for abandonment, reflecting an ancient fear that the sun might abandon Earth. As far back as

2000 BC, Babylonian astronomers discovered how to predict accurately when the moon would obscure the sun. Historical records show that an eclipse of the sun in 585 BC inspired such fear among warring Medes and Lydians in what is now Turkey that they agreed to make peace.

Over the centuries, observations of solar eclipses have produced important scientific results. During an eclipse in 1868, the English scientist Norman Lockyer discovered the element helium, which makes up a large part of the sun’s burning mass of gases. Starting in 1919, scientists began measuring starlight patterns during solar eclipses in an effort to prove Albert Einstein’s theory of relativity. More generally, the blockage of intense solar light during an eclipse allows scientists to measure the size, activity and composition of the star that sustains life on Earth. Said Naylor: “We have basically just a few seconds to get an enormous amount of information.” Astronomers said that data gathered during the latest eclipse may confirm suspicions about the changing diameter of the sun, which is believed to be 4.5 billion years old and slowly diminishing. For their part, American and Mexican scientists launched a small rocket 50 miles into the atmosphere during the eclipse from Santiago Ixcuintla, about 200 km north of Guadalajara along the Pacific coast. Although the $184,000 mission was supposed to record information about solar particles, it failed because of technical difficulties.

Most of those gathered for the century’s most spectacular celestial event said that they were awestruck by the eclipse. Said Andrea Hansen, a Toronto screenwriter who saw the eclipse in Baja California, Mexico: “It makes you feel a part of the universe.” Added Watson, who saw his first eclipse from Quebec’s Gaspé Peninsula in 1972: “You really get hooked by these astronomical events.” Clearly, for addicts, last week’s celestial fix was truly a glimpse of heaven.

DIANE BRADY with JAMES DEACON in Toronto

JAMES DEACON