Beyond earth's atmosphere, beyond even the orbit of the moon, lies space. By definition this is supposed to be empty, an interval separating things from each other, but instruments sent out to probe this space reveal that it is far from empty. The vacuum is filled with a variety of forces, many of which reach the earth and some of which affect life here. The most powerful of these forces come from the star we call our sun.
The sun is a dense mass of glowing matter a million times the volume of the earth and in a permanent state of effervescence. Every second, four million tons of hydrogen are destroyed in incredible explosions that start somewhere near the core, where the temperature is 13 million degrees Celsius, and send fountains of flame shooting thousands of miles out into space. In this continuous and unimaginable holocaust, atoms are split into streams of fast-moving electrons and protons that rush out into space as a solar wind that buffets all the planets in our system. Earth falls well inside the sun's "atmosphere" and is constantly exposed to the changes in its weather. Scattered over the face of the sun like acne are spots of even more violent activity that flare up from time to time. These are usually about the size of earth, and sometimes the rash spreads quickly and the sun erupts in a bout of bad weather that produces magnetic storms in our atmosphere as well.