How Fast Does The Earth Spin?

How fast is Earth's rotation?

At the equator, Earth's surface moves at about 1,037 mph (1,670 km/h), according to NASA. The planet completes one full rotation every 23 hours, 56 minutes, and 4 seconds, which is called a sidereal day. The 24-hour day we use is the solar day, slightly longer because Earth has to rotate a bit extra to face the Sun again as it moves through its orbit. At the equator, you're covering roughly 25,000 miles in a single day, just by standing still.

Does Earth spin the same speed everywhere?

No. Rotation speed depends on latitude. At the equator, the surface moves about 1,037 mph. At 45 degrees latitude (roughly New York or Minneapolis), the speed drops to about 730 mph. At the North or South Pole, you're essentially standing still, just rotating in place once per day. The reason is geometry: every point on Earth completes one full rotation in the same amount of time, but points farther from the axis trace bigger circles, so they have to move faster to keep up.

Why don't we feel Earth spinning?

Because Earth's rotation is constant and steady, not accelerating. Humans feel acceleration, the change in speed or direction, not motion itself. You don't feel a smooth highway drive at 70 mph either, until you brake suddenly. Earth has been spinning at roughly the same rate for billions of years, and everything on the surface (air, oceans, you) moves with it. The only physical evidence of rotation we can detect is indirect, like the Coriolis effect on weather patterns or the way a Foucault pendulum slowly shifts its swing direction.

Is Earth's spin slowing down?

Yes, very slowly. The Moon's gravity creates tides that gradually drain rotational energy from Earth, lengthening our day by about 2 milliseconds per century. Millions of years ago, Earth's days were significantly shorter. Around 1.4 billion years ago, an Earth day lasted only about 18 hours. The slowdown is one of the reasons the Moon is drifting away from Earth at about 1.5 inches per year. It's getting a small share of Earth's rotational energy as it goes.