The human eye is a remarkable instrument, well adapted to reveal the world around us. But it’s not very good at seeing the universe beyond our own planet. The universe is filled with forms of energy that are invisible to our eyes alone. Yet these wavelengths carry important information about the objects that produce them.
An example is the infrared. It’s produced in abundance by relatively cool astronomical objects, such as red stars, the clouds of gas and dust that give birth to stars, and the comets, asteroids, and dust around stars.
Unfortunately for astronomers, though, water vapor in the atmosphere absorbs most of the infrared energy that reaches Earth. In effect, that creates a fog that obscures the infrared universe.
To see the infrared, astronomers must loft their instruments above the fog. Most mountaintop observatories can see some infrared wavelengths, with those on taller mountains getting a better view. Balloons and airplanes climb even higher. A flying observatory known as SOFIA, for example, soars above almost 99 percent of the water vapor in the atmosphere.
And the best view of all comes from space. Over the last three decades, the United States and others have launched about a dozen infrared space telescopes, of different sizes and capabilities. The largest of them all was the European Herschel Space Telescope, which ended its mission a few months ago.
But another one is still going, and we’ll have more about that tomorrow.
Script by Damond Benningfield, Copyright 2013
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