Chemical Factory
Stars are chemical factories. They begin with hydrogen, the most basic element of all. Over time, they forge heavier elements. And when they die, they expel many of these elements into space, where they can be incorporated into NEW stars.
A star spends most of its life producing helium. That's happening now inside our own star, the Sun. It's also happening inside Regulus, the brightest star of Leo, the lion, which rises in early evening.
Stars are made primarily of hydrogen, the lightest and simplest chemical element. Under the intense pressure in a star's core, the nuclei of hydrogen atoms link together -- a process called nuclear fusion. When four atoms of hydrogen link up, they make one atom of helium.
But the rate at which helium is created varies from star to star. The regulator for this process is the star's mass -- in essence, how heavy it is. As the mass increases, so does the rate of nuclear fusion in its core. That makes the star hotter, which is reflected in its color.
The surface of Regulus, for example, is blue-white. That means it's much hotter than the surface of the Sun. From this and other measurements, astronomers conclude that Regulus is about three and a half times as massive as the Sun. At that mass, it's "burning" through its hydrogen in a hurry. So Regulus will move on to the next process much quicker than the Sun will -- making the next elements beyond helium.
What's happening inside another star tomorrow.
Script by Damond Benningfield, Copyright 2003
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