A fish-eye image shows a laser firing from the Gemini North telescope in Hawaii. The laser causes atoms in the upper atmosphere to glow. Small mirrors inside the telescope adjust their shape many times per second to bring that glow into sharp focus. The adjustments also bring astronomical objects near the laser beam into sharp focus, vastly improving the telescope's images. Astronomers use the laser, which was invented 50 years ago, for many tasks, including measuring the distance from Earth to the Moon and looking for gravitational waves. [Gemini Observatory]
Imagine life without supermarket checkout scanners, high-speed Internet, DVDs, Lasik surgery, or a hundred other gizmos. It's what life was like half a century ago -- before a physicist named Theodore Maiman invented the laser. He demonstrated the first successful laser 50 years ago this month.
A laser pumps energy into some sort of material -- in Maiman's case, a ruby crystal. The energy "excites" the atoms in the material, causing them to produce a single wavelength of light. And unlike the beam of a flashlight, in which the light spreads out in all directions, the waves in a laser beam are all moving in the same direction, like soldiers on parade.
A laser's narrow, focused beam can carry a great deal of energy or information, making lasers highly versatile tools. They cut metal, carry telephone calls and emails, and burn CDs. Doctors use them as surgical tools, and public speakers use them as pointers.
Scientists use lasers to explore the universe. They use them to measure the distance from Earth to the Moon, to sharpen the views from their telescopes, to look for evidence of gravitational waves, and much more. And like everyone else, they use them to store and transmit information -- information often obtained with the help of this shining invention.
More about lasers in astronomy tomorrow.
Script by Damond Benningfield, Copyright 2010
For more skywatching tips, astronomy news, and much more, read StarDate magazine.