Does the Earth spin fast or slow?
How and why? ANSWER from Stephanie Wong on 21 March 2003: That depends on what you mean by fast and slow. To make a crude approximation, take the Earth, rotating once in 23.9 hours. The radius of the Earth at the equator is 6,378 kilometres. So, Circumference of Earth = 2(pi)(radius) = 40,074 kilometres Speed = circumference/time = 1678 kilometres/hour That’s pretty fast! This is the speed of a point on the equator as it rotates about its axis. As you go nearer and nearer to the poles (or go inside the Earth), the speed will decrease, since you are rotating about a smaller radius (think of dividing the Earth into many thin discs. Sweeping out a smaller circumference in the same amount of time results in less speed. So, depending on what you think is fast, and the reference frame from which you measure Earth’s speed, you can decide whether the Earth moves fast. For example, standing on Earth now, I don’t sense the Earth’s movement because I am moving equally as fast with the Earth. So i
