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The Earth Is Spinning At Incredible Speeds, So Why Don't We Feel It?

You feel the centrifugal force on a roundabout, so why not Earth?

James Felton

James Felton

James Felton

James Felton

Senior Staff Writer

James is a published author with four pop-history and science books to his name. He specializes in history, strange science, and anything out of the ordinary.

Senior Staff Writer

Edited by Francesca Benson
author

Francesca Benson

Copy Editor and Staff Writer

Francesca Benson is a Copy Editor and Staff Writer with a MSci in Biochemistry from the University of Birmingham.

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A woman with hair going sideways, rather than with gravity.

Ever noticed how people's hair isn't blown sideways by the spin of the Earth?

Image credit: smolyaninov/shutterstock.com

The Earth is spinning at around 1,000 miles per hour (1,600 kilometers per hour). So why do you, on Earth, not feel like you are hurtling along at these incredible velocities?

When you get on a roundabout and it spins, you feel like you are being pushed outwards. This is the (not real) centrifugal force. There is no external force pushing you off the play equipment – what you are actually feeling is the result of your own inertia, or the tendency for objects in motion to remain in motion in a straight line at the same velocity unless another force acts upon it. 

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You might extrapolate from that that you must experience the same feeling of being pushed outward as the Earth spins, and you'd be correct. In fact, the planet bulges at the equator because of it, and as a result, you weigh less at the equator because you are further away from the bulk of the Earth's mass.

Forces that change the shape of the Earth also affect you, standing on said Earth. You are affected by it, but it is overwhelmed by gravity.

"The acceleration of gravity is about 9.8 m/s^2 on the Earth's surface, and the reduction of that due to the rotation of the Earth at the equator, where things are moving the fastest, is about 0.03 m/s^2," professor of physics and optical science at the University of North Carolina at Charlotte, Greg Gbur, explained to Live Science, "which is measurable but really tiny compared to what we feel from gravity itself, so we don't notice it."

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Relative motion is the only motion you have to worry about (thank Einstein), which leads us to the air. Think about how, in a car, the air feels stationary – but if you were to stick your head out the window like a dog, you would feel the air slamming against your face and making your ears/hair/loose skin flap. As the Earth spins it drags our atmosphere along with it, so we aren't battered constantly by incredibly high winds every moment of our waking lives.

The Earth's motion is relatively smooth, though it is slowed and sped up by various factors, including earthquakes. If it were more jerky, you would feel the acceleration and deceleration, but you do not feel constant velocity. Which is good, because the planet orbits the Sun at 107,000 kilometers per hour (66,500 miles per hour), and the Sun hurtles through the galaxy at 828,000 kilometers per hour (514,500 miles per hour), which are much faster than, for example, your car. 

If the Earth were to suddenly stop, however, you would feel forces aplenty.

[H/T: Live Science]

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All “explainer” articles are confirmed by fact checkers to be correct at time of publishing. Text, images, and links may be edited, removed, or added to at a later date to keep information current.  


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