Planetariums Take Viewers on a Trip Through Space

28 September 2010

The original Carl Zeiss projector at the Smithsonian's Albert Einstein Planetarium projects an image from the show "Infinity Express: A 20-Minute Tour of the Universe" .

STEVE EMBER: I’m Steve Ember.

BARBARA KLEIN: And I’m Barbara Klein with EXPLORATIONS in VOA Special English. A planetarium is a theater with a rounded ceiling onto which images of the stars and planets are projected. Planetariums give educational shows about astronomy and what you can see in the night sky. Today, we tell about the past, present, and future of planetariums. And, we visit the Albert Einstein Planetarium at the Smithsonian National Air and Space Museum in Washington, D.C.

(MUSIC)

STEVE EMBER: Since ancient times, humans have worked on ways to understand and represent the movement of the stars and planets. Experts credit the Greek astronomer Archimedes with developing the earliest known device to show the daily movement of the planets. He lived more than two thousand years ago. These mechanical devices that show the relative placement and movement of the planets and moons are sometimes called orreries. Over the centuries, scientific thinkers worked to develop these devices and improve their accuracy and complexity.

The words “orrery” and “planetarium” were once used interchangeably. Today, the world “planetarium” generally means a theater inside a dome.