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  Our Sun

Energy and Work

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Electrical Generation

Our Sun



The sun. The center of our solar system. It gives off heat, light, and radiation. The sun is actually a ball of glowing gases. It is hotter than anything we can imagine. It is so hot that we can feel its heat even though we are 93 million miles away from it.

If you could look inside the sun, you would see four different layers: the core, the radiative zone, the convective zone, and the photosphere.

The core is the center of the sun. Nuclear reactions take place here, producing energy.

The radiative zone is the second inside layer. Energy travels from the core outward to this layer in the form of radiation.

The convective zone is the third layer. Huge waves of energy swirl around here, carrying the heat outward.

The photosphere is the outside layer of the sun. This is the visible layer, where light is emitted.


Producing Energy (Fusion)
The sun produces heat, light, and radiation through the process of fusion. Fusion occurs when a substance is so hot that atoms gain and lose particles, actually changing from one type of element to another. The sun converts hydrogen to helium in a three-step process.

  1. Two hydrogen atoms combine. This forms deuterium, also called heavy hydrogen.
  2. Deuterium joins with another hydrogen atom. This forms a type of helium (helium-3).
  3. Two helium-3 atoms collide, producing ordinary helium and two hydrogen atoms

Energy is released at every step. The energy comes in the form of tremendous heat, radiation that can kill us, and light that we need to survive.

The Sun's Role in Life
The sun not only produces light, but it allows most other types of energy to exist. Certainly life on earth wouldn't exist without the sun. For example, the sun allows plants to make food in a process called photosynthesis. Photosynthesis allows for almost all other living organism to survive.

Think about a food chain. A small plant takes the sun's light (energy) and produces food. The plant is eaten by a tiny little shrimp. The shrimp is eaten by a fish. The fish is eaten by you. If the sun died, the food chain would collapse. No plant. No shrimp. No fish. No you.

The sun also is the source for many other types of energy. For example, wind energy requires the sun. The sun heats up air in our atmosphere. The hot air rises. Cool air moves in, and the air moves around as wind. Or take biomass energy. The light from the sun grows the plants (trees, corn, sugarcane) that we use for energy. Or how about solar energy? The sun's light shines on panels that convert light to electricity. Fossil fuels? The sun created those too. Sunlight grew those plants and animals that became oil, coal, and natural gas.

The Sun's Lifespan
Our sun is about 5 billion years old. It is nearly half way through its life. Five billion years from now the sun will run out of hydrogen gas. When that happens the sun will grow about one hundred times bigger than it is right now. And then it will start to become a white dwarf. Our sun will become a glowing hot ember, about the size of Earth. It will eventually cool down.