Arcturus

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FROST: Arcturus is one of the brightest stars of our summer sky, known ever since men first turned their eyes in wonder toward the glories of the heavens.

Arcturus is the brightest star of Bootes, the herdsman. It's high in the sky at nightfall. You can find it by following the arc of the Big Dipper's handle across the eastern sky until you come to the first bright star: Arcturus.

Edwin Frost, a retired director of the University of Chicago's Yerkes Observatory, was waxing poetic about Arcturus 75 years ago this week. That's because the star was about to play a key role in the opening of the 1933 World's Fair in Chicago. The star's light would trip a switch to illuminate the fair.

FROST: It is a yellow sun, having a diameter about 25 times that of our own Sun, and radiating about 100 times as much light. It is highly probable that it has been sending out its light for hundreds of millions of years. It has advanced to a state of development not greatly different from that of our own Sun.

Most of Frost's dossier was correct -- all but that last part. Arcturus is farther along the evolutionary scale than the Sun is. It's "burned" through the hydrogen in its core, leaving an "ash" of helium. It's a process that astronomers didn't understand until several years after the world's fair -- a gala event that was illuminated by a star.

More about Arcturus tomorrow.

Script by Damond Benningfield, Copyright 2008

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