By Grant Holland
The temperature is 7 million degrees F. The core contains 40 percent of the sun's mass in 10 percent of the volume. It is the hottest part of the sun.
Photosphere is the visible surface of the Sun that we are most familiar with. Since the Sun is a ball of gas, this is not a solid surface but is actually a layer about 100 km thick very thin.
Layer above the photosphere where the temperature rises from 6000°C to about 20,000°C. This layer gives off a reddish color for the sun.