Outshining the brilliant night skies


Stars: Half of the world's people -- 96 percent of those in the United States -- cannot experience true darkness and dazzling views of the Milky Way because of artificial light, scientists say.

September 10, 2001|By Frank D. Roylance | Frank D. Roylance,SUN STAFF

On a dark night many years ago, when Philip Ianna was only 13 or 14, he was riding in a truck loaded with other Boy Scouts from Philadelphia, when nature called.

They were perhaps an hour northwest of the city, headed for a weekend of country camping.

The driver pulled over, and the boys piled out to relieve themselves. But while everyone else looked down, Ianna looked up.

"I still remember how black the sky was, the uncountable number of stars, numbers I had never imagined might be there," he says. "It knocked my socks off, and I basically never recovered."

Ianna became an astronomer. He's a professor emeritus now, retired from the University of Virginia. He has been privileged to observe the stars from some of the darkest places on the planet.

But outside Philadelphia, and in places where most of the Earth's people live today, true darkness -- and the dazzling starscapes that once dominated the night everywhere -- are as extinct as the woolly mammoth.

An expanding profusion of artificial lighting is obliterating the night.

This summer, a team of scientists from the University of Padua, Italy, and the National Geophysical Data Center in Boulder, Colo., published a global atlas (www.lightpollution.it) which shows, in map form, where the stars can still be seen, where they are fading, and where they are nearly gone.

They report that for about half the world's population -- and more than 96 percent of the population in the continental United States and Europe -- "night" is no darker than twilight. Two-thirds of the U.S. population can never see the Milky Way where they live.

It is the extinguishment of a natural heritage, astronomers say, that has gone largely unnoticed, even by people who would march to defend a forest or wetland.

"When a person sees the sky from a light-polluted city, they may see a handful of stars, perhaps two or three dozen at most," says Christopher A. Bortz, an observing coordinator for the Northern Virginia Astronomy Club (NOVAC).

"But when the eye glimpses not a few stars, but thousands -- so many that they can't be counted -- then a person gets a sense of the true scale of the universe," he says.

"This is what the ancients saw, and what inspired them to create many of the world's great wonders. And it is what modern man is constantly depriving himself of."

Tom Dietz, also with NOVAC, leads amateur astronomers on observing trips to Spruce Knob, W.Va., one of the few truly dark spots remaining east of the Mississippi River. "We've gotten used to having our [night] skies an orangey-gray color," he says -- skies ablaze with wasted light that shines up, instead of down.

As diurnal creatures, the night is alien to us, darkness something to be banished. We forget that inky darkness is the natural state of the universe, the "default" condition that prevails everywhere until a star, such as our sun, lights up nearby, or a galaxy of billions of stars wheels into view.

"Get outside the Milky Way's spiral disk, into intergalactic space, and most of the sky would look utterly black to the naked eye," says Phil Plait, an astronomer at Sonoma State University in California. "You would see only five or six galaxies [our local cluster] which would appear as faint smudges in the sky."

"Inside our galaxy, pretty much everywhere you looked you would see what we see now -- lots of stars, with the band of the Milky Way going across," he says.

Most American children, however, grow up without ever seeing their galaxy, or knowing outdoor darkness so deep they can't see their own bodies. They're oblivious to the existence of more than the handful of bright stars and planets visible from the cities and suburbs.

Imagine trying to describe to them the glowing carpet of stars above the remote Inter-American Observatory at Cerro Tololo, in the Chilean Andes.

"I just always found it to be a thing of indescribable grandeur, the dark, pure night sky of the Andes," says Bob Williams, a former director at Cerro Tololo, and later director of the Space Telescope Science Institute in Baltimore.

Many more bright stars hang in the skies of the Southern Hemisphere than ours. And many thousands more faint stars emerge from the blackness at Tololo, in the clear, dry air at 8,000 feet.

Observers enjoy startling naked-eye views of the crowded hub of the Milky Way's spiral, and two nearby galaxies called the Large and Small Magellanic Clouds, Williams says.

"If one could experience 15 minutes in Tololo," he says, "there isn't a soul who wouldn't look up and say, `My God!'"

In Europe and the United States, encounters with dark skies now demand careful planning and considerable travel. Or serendipity.

This month, Stephen P. Maran, press officer for the American Astronomical Society, was vacationing with his wife on the Greek island of Santorini.

The streets in the village of Oia were still lively, still full of people at 11 p.m., he says.

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