1 Answer

  You don’t feel the Earth spin because you, the atmosphere, skyscrapers, and everything else are spinning along with the Earth at the same constant speed.It’s the same sensation as when you’re riding in a car or flying in a plane – as long as the ride is going smoothly. A jumbo jet flies at about 500 miles per hour – that’s about 800 kilometers an hour – about half as fast as the Earth spins at its equator.

But if you close your eyes, you don’t feel like you’re moving at all. And when the flight attendant comes by and pours coffee into your cup, the coffee doesn’t fly to the back of the plane. That’s because the coffee, the cup and you are all moving at the same rate as the plane.

http://earthsky.org/earth/why-cant-we-feel-earths-spin

Likewise, Earth is moving at a fixed rate – and we’re all moving along with it. Now imagine being on the jumbo jet again – think about what happens when the pilot suddenly speeds up or slows down the plane. You sometimes sense this change as a feeling of being pushed into your seat. In the same way, if the Earth were suddenly to speed up or slow down, you would definitely feel it.

But as long as Earth spins steadily – and moves at a constant rate in orbit around the sun – you as an earthly passenger move right along with it.

If the earth suddenly started to speed up we’d fall over backwards, and we’d have to lean into the direction of the motion to stand. If the earth were speed up enough that it spun once every hour and twenty minutes, we would fly off its surface. The next time you’re in a car or a plane traveling at a constant speed, close your eyes and try to feel that you’re moving. You won’t be able to tell.

Ancient humans noticed that the stars, and the sun and the moon all appeared to move above the earth. Because these people couldn’t feel the earth move, they logically interpreted this observation to mean that the earth was stationary and the “heavens” actually physically moved above us.

With the exception of the beliefs of ancient Greek scientist Aristarchus, who first proposed a heliocentric (“Sun centered) model of the universe, this geocentric (“Earth-centered”) idea was upheld for a long time. It would be Copernicus’s 16th Century heliocentric model that, although it was not without errors, would eventually convince the world that the earth spun on its own axis and that it moved around the sun.