Motions of the Earth Earth's Rotation on Its Axis

About the different motions of the earth that are going on around us astronomically and geologically including the earth's rotation on its axis.

MOTIONS OF THE EARTH

2. EARTH'S ROTATION ON ITS AXIS

Daily rotation is the only motion of the earth that all of us can observe directly, simply by watching the sun or moon rise or set. In each 24-hour rotation, the earth revolves at 1,035 mph, as measured at the equator. However, the friction of the ocean tides against the earth's surface has been slowing our planet's rotation by 1/1,000 second per century. Thus, 2 million years ago, when our distant ancestors were alive, the earth's slightly faster rate of rotation made their day 20 seconds shorter than ours.