Scientists estimate that the sun is 4,600,000,000 years old. They believe that it was formed when the force of gravity pulled gases and dust together in space. As this mass of gases and dust came together, it continuously contracted, or got smaller. As the mass pulled together in a ball shape, the pressure of the gases increased until those at the center reached a temperature of 2,000,000°F. At that point, nuclear energy began at the center, heating the gases and causing the sun to shine.
Today, the sun is the source of almost all of the light, heat, and energy on earth, and all life, human, animal, and plant, depend on it. Even though the sun is still a gaseous mass, its temperature varies. On the surface of the sun, the average temperature is 4,500°F, while in the center it reaches 27,000,000°F.
Because the sun is a star, and nearer to the earth than any other star, scientists study it to learn more about the stars that are much farther away.
The hot gases on the sun’s surface give off HUGE amounts of light and heat, but very little of this light and heat ever reach the earth. In fact, only two-billionths of it, ever does. The rest is lost in space during the 8 minutes and 20 seconds that it takes the sun’s light to reach the earth. And lucky for civilization that it does, or the entire earth and the other planets could not survive.
