Take a look at your thumbnail, and then imagine a spot on the Sun that’s the same size. This tiny spot would be really bright—as bright as a million candles shining all at once!
The Sun is our brightest and most important source of light. At any given moment, it sends out 383 billion billion megawatts of light energy. (That’s 383,000,000,000,000,000,000,000,000 watts!) Compare this to a light bulb in your home, which probably gives between 50 and 150 watts.
Only a small amount of the Sun’s light reaches us, because most of it speeds off into space, away from Earth. “Speed” is right—light is the fastest thing in the universe!
The few rays that do arrive on Earth allow every living thing on the planet to survive. Without light, our world would be completely dark and really cold—so cold, everything would freeze solid. Life simply couldn’t exist without light.
