The Sun is basically a huge spinning ball of hot gas. It is approximately 90% hydrogen, 10% helium, and .1% lithium, carbon, and other elements. Okay, so that's easy enough to understand. But where does such a huge mass of gas come from? How does it continue to produce energy, and why is it so darn hot?
We can find the answers to these questions by looking at the very center of the Sun, the core.
The Sun exists because of a process called fusion or the proton cycle. In the core of the Sun, the temperature is so hot that the atoms are constantly colliding and tearing apart the hydrogen atoms to form separate protons, neutrons and electrons. These are the parts that make up an atom. The "freeing" of these particles is what lets the proton cycle take place. There are three basic reactions involved in this process. After these reactions have taken place, hydrogen has been turned into helium.
Now, you may be wondering exactly why this has any importance to the Sun and what it does. Well, the most important thing to remember is that each time helium is formed, a release of energy takes place. It is through these reactions that the Sun gets its energy. And all of them take place in the core!
Here is an illustration that shows the different layers of the Sun.
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