Every day the sun radiates, or sends out, an enormous amount of energy. It radiates more energy in one second than people have used since time began.
Where does all this energy come from? It comes from within the sun itself. Like most stars, the sun is a big gas ball made up mostly of hydrogen and helium gas. The sun makes energy in its inner core in a process called nuclear fusion.
Only a small part of the solar energy that the sun radiates into space ever reaches the earth, but that is more than enough to supply all our energy needs. Every day enough solar energy reaches the earth to supply our nation's energy needs for one and a half years!
It takes the sun's energy just a little over eight minutes to travel the 93 million miles to earth. The solar energy travels to earth at a speed of 186,000 miles per second, the speed of light.
Today people use solar energy to heat buildings and water and to generate electricity.