At what speed is the earth moving?
Our dizzy old world spins and whirls in several different directions,each at a different speed. Every year it swings in a complete orbit around the sun. It makes this 600 million mile trip at an average speed of 18 1/2 miles per second. Meantime, the sun and its orderly family are moving in an immense journey around the Galaxy. It takes 200 million earth years to complete one of the cosmic trips. The sun, the orbiting earth and other members of the Solar System travel this stupendous journey together. In neat formation, they swoop through the starry heavens at an average speed of 170 miles per second. Our dizzy globe also spins around on its axis like a top. The axis is a line through the center from pole to pole and the earth completes one turn with every calendar day. However, because it turns on an axis, the exact poles do not spin around at all. As the globe bulges toward the equator, the surface rotates faster. The wide equator must rotate fast est. Every spot on this bulging line
