Parts of the Sun

The sun is made of gas and has no solid surface as Earth does. However, it still has a defined structure. The three major surface areas of the sun are shown in the upper half of Figure 1:

• Core
• Radiative Zone
• Convective Zone

Photo courtesy SOHO consortium. SOHO is a project of international cooperation between the European Space Agency (ESA) and the U.S. National Aeronautics and Space Administration (NASA). Figure 1. Basic overview of the parts of the sun. The flare, sunspots and the prominence are all clipped from actual SOHO images.

Above the surface of the sun is its atmosphere, which consists of three parts as shown in the lower half of Figure 1:

• Photosphere
• Chromosphere
• Corona - extremely hot outermost layer extending outward from the chromosphere several million miles or kilometers

We will see that all of the major features of the sun can be explained by the nuclear reactions that make its energy, the magnetic fields that are caused by the movements of the gas, and the immense gravity.