Why does the sun shine?

Like other stars, the Sun is made up mainly of hydrogen gas. The temperature at the Sun's surface is about 10,000 degrees F, but rises to about 27,000,000 degrees F at its core. The temperature and pressure are so high there that nuclear reactions take place. Hydrogen atoms smash into each other and stick to form helium, and release an enormous amount of energy in the process.

H atoms colliding to form He and releasing energy. (257 K Quicktime)

Last modified prior to September, 2000 by the Windows Team

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