## Can we feel the Earth spin? (Beginner)

Are we ever able to feel the Earth spin? Can other animals or creatures feel it spin or react to it? Why aren't we dizzy, but would we be if we could feel it? I am a parent of a child asking these questions over and over, convinced she can feel it. Maybe children can.

At the equator, the Earth is spinning at 1000 miles per hour about its axis and moving at 67,000 miles per hour around the Sun. With all this motion, you would expect to feel something, right? Well we don't feel anything because all of the motions are almost completely constant.

When you take a really smooth plane or train ride, you don't feel the motion unless the plane/train slows down, speeds up, or hits a bump in the road. So as long as there is constant motion, we don't feel it. Children do amaze me with their ability to perceive things, but I would be very surprised if your daughter could feel the slight wobbles the Earth has as it spins. I don't think the wobbles would be enough (could we feel them) to make someone dizzy.

There is also another way in which we could indirectly feel the Earth's spin. Above we said that the Earth spinning is an example of almost constant motion. The reason we said "almost" is that the Earth's spin carries us around in a circle, not in a straight line. It's a very big circle, and it takes a long time to go around, but qualitatively it is the same thing that happens on a spinning amusement park ride, where it feels like you're being flung outward as the ride spins around. The spinning Earth is flinging us away from its surface a tiny bit, so that we weigh a little less than we would otherwise, simply because we are not being held down to the surface as tightly.

However, this is a very small effect. At the equator, your weight is reduced (compared to a non-spinning Earth) by about 0.3%; the effect weakens as you go north or south, and once you reach the north or south pole it disappears completely because the Earth is not spinning there. So if you can feel differences in your weight of 0.3% (about half a pound for a 150 pound person), and if you travel from the equator to the north or south pole, then technically speaking, you could feel the effects of the Earth spinning. On the other hand, people's weight naturally fluctuates more than 0.3%, so it's unlikely that you'd be able to disentangle this from other effects (like whether or not you had just eaten lunch).

This page was last updated on June 27, 2015.

### About the Author

#### Sabrina Stierwalt

Sabrina was a graduate student at Cornell until 2009 when she moved to Los Angeles to become a researcher at Caltech. She now studies galaxy mergers at the University of Virginia and the National Radio Astronomy Observatory in Charlottesville. You can also find her answering science questions in her weekly podcast as Everyday Einstein.