Chapter 1. Overview
1.1 Overview
Most of us think of the Sun as a quiet ball of steadily burning gas that provides the light and heat necessary for life to exist on Earth. As it turns out, our Sun is anything but quiet. Unpredictable explosions on the surface release tons of material that races out into the solar system causing communication satellites to malfunction, power grids on Earth's surface to overload, and the eerie northern and southern lights to glow at high latitudes. Inside the Sun, nuclear fusion operating at 15 million degrees combines hydrogen atoms into larger helium atoms in a process that releases energy that keeps the Sun from collapsing under its own weight.
As it turns out, many of the stars in the night sky are very similar to our Sun. If astronomers can understand the physical mechanisms that cause our Sun to act as it does, then those same principles should apply to the many distant Suns we see in the heavens. Understanding the physical processes that govern our Sun will help us better understand the distant stars twinkling in the night sky.