'Bizarre Stars' Planetarium show offers new glimpse at the galaxy

January 12, 1991|By Phyllis Brill | Phyllis Brill,Evening Sun Staff

Have you ever wondered how a star is born? Or imagined seeing one explode into a supernova or disintegrate into a black hole. What if you could get close enough to the sun to see what's at its core?

Contemplators of the world beyond can experience all this and more at "Bizarre Stars," the media show that opens today at the Davis Planetarium in the Maryland Science Center.

Well, you can't actually see these things happen, but you can see them simulated on the planetarium's 50-foot-wide domed ceiling that will be transformed into a sky full of stars with the flick of a switch. Using a couple dozen slide projectors, about 70 special effects and some laser graphics, planetarium wizards will give a 30-minute lesson on everything from finding stars to fingerprinting them. And all that a visitor has to do is sit back in a comfy chair in the circular auditorium and gaze heavenward.

It's as if you walked outside on a perfectly clear night and ordered the stars to perform for you. With the magic of indoor technology, planetarium choreographers can make stars come to life with a simple stage direction or two.

"What we try to do in this show is give a feel for the different stars that are visible and for the great variety there are in terms of color, size, brightness, temperature or distance from us," says Jim O'Leary, director of the Davis Planetarium and IMAX Theater.

He and his staff of about six technical experts produce two to four planetarium programs a year. Besides being shown at the Maryland Science Center, many of the shows are also sold to other planetariums that cannot afford to produce their own -- some as far away as Australia and Japan.

In "Bizarre Stars," attention is focused initially on the constellation Orion, an hourglass-shaped grouping of seven major stars that suggested the mythical hunter Orion to the ancients. This configuration, which is easily recognizable in the winter sky, makes a handy reference for discussing various types of stars, says O'Leary.

For instance, there's the nebula, or birthplace of stars. In Orion, it's the cloudy area near the hunter's belt where hundreds of baby stars, less than a million years old, are forming. And there's Betelgeuse, the bright red star in the armpit of the giant -- an example of a very large star.

"And the star on the bottom right is Rigel, which could become an exploding star in the distant future," says O'Leary.

Visitors will learn that a star's color suggests its temperature and that its distance from Earth is measured in light years -- the distance light travels in a year's time.

Hot stars like Rigel look very white, while cooler stars like Betelgeuse are orange-red. Rigel is so far away from Earth that the light we see from it actually began its journey in the late 11th century, while Sirius, a much closer star, is a mere 8 1/2 light years away.

Veteran stargazers probably know that the sun, too, is a star; in fact, it's the closest one to Earth and the only life-sustaining star known to man. Because it's so familiar, the sun is used in the program to illustrate various attributes of a star.

Visitors will get a close look at the sun's gaseous interior, learn how it releases heat and light as energy, and discover that its spectrum of light, like a fingerprint, can be used to identify its unique characteristics.

Despite its fascinating makeup, astronomers sometimes joke that the sun is only an "ordinary, middle-aged star," says O'Leary. The 5-billion-year-old star has about 5 billion more years of life in it, and when it dies it probably won't be a very spectacular death, he says.

On the other hand, there are more bizarre stars in our galaxy, like binaries. A binary system consists of two stars that exist so close to one another that they are in constant contact, "tugging at each other and reacting violently for tens of millions of years," says O'Leary.

Although all stars are born in essentially the same way -- out of clouds of dust and gas pulled together by gravity -- they die very different deaths. When the sun burns up, its core will ultimately collapse to a small, dense white dwarf star.

The death of other stars can be more stunning. A large star will burn quickly, throwing off its outer layers violently in a supernova. The core may collapse to a very dense neutron star or even a black hole, where gravity is so strong not even light can escape, leaving a dark space in the sky.

Nearly as fascinating as these phenomena are the techniques used to re-create them in the planetarium's theater. The centerpiece of the 140-seat auditorium is a huge projector that looks like a satellite or, to less scientific minds, a giant grasshopper. The robot-like contraption has 32 lens assemblies, each of which can project more than 300 stars on the dome just as they actually exist in a Baltimore sky at any given time of the year.

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