When we talk about Earth’s rotation, we usually mean how fast it spins around its own axis. Imagine the Earth as a giant spinning top. This spin gives us day and night.
The Earth takes approximately 24 hours to complete one full rotation. But how fast is it spinning? To find out, let’s look at the equator, the widest circle around the Earth. The circumference of the equator, or the distance all the way around, is about 40,075 kilometers (24,901 miles).
Now, if the Earth rotates once every 24 hours, then at the equator, the speed is:
Speed=Distance/Time
Speed=40,075 km/24 hours
Speed≈1,670 km/h
So, Earth’s surface at the equator is moving at about 1,670 kilometers per hour (or around 1,038 miles per hour) due to its rotation! That’s faster than most airplanes fly. However, if you move away from the equator toward the poles, this speed decreases. At the poles, it’s zero because you’d be standing on the rotation axis.
Earth is also slowing down across the years by 1.8 milliseconds every century. This suggests that 600 million years ago, the Earth only had a 21-hour-long day. Yet, contrary to the usual, 2020 saw a spike in the speed of Earth’s rotation, with all 28 shortest days ever recorded occurring in 2020. Scientists believe this is a temporary event, which the excessive melting of glaciers might have caused, but these minute changes can stir up GPS and satellite systems.
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