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Moon and Jupiter

May 8, 2010

The human eye is wonderfully adapted for conditions here on Earth. It sees the wavelengths of light that the Sun produces in greatest abundance -- the optical portion of the electromagnetic spectrum.

As we gaze out into space, though, we need to look at all the other wavelengths to find out as much as we can about stars, planets, and other objects.

An example is Jupiter, the largest planet in the solar system. It's a little below the crescent Moon at first light tomorrow, and looks like a brilliant star.

Optical wavelengths show us that Jupiter's fatter through the equator than the poles -- a result of the planet's fast rotation on its axis. They also show us that Jupiter's clouds form globe-circling bands, punctuated by giant storms.

Infrared wavelengths, which are too long for the eye to see, show us that Jupiter radiates more heat into space than it receives from the Sun -- perhaps as a result of a "rain" of liquid helium onto the planet's core. And even-longer radio waves show that Jupiter has a strong magnetic field, generated by a "dynamo" effect deep inside the planet.

At the other end of the spectrum, short ultraviolet wavelengths show powerful auroras at Jupiter's poles, like the northern and southern lights here on Earth. The auroras heat Jupiter's atmosphere, helping create an organic "haze" high in the sky.

All of these wavelengths combine to provide a better picture of Jupiter -- a picture of a complicated giant.

Script by Damond Benningfield, Copyright 2010

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