# How is the earth's speed measured

## How fast is the earth turning?

### Oliver from Broistedt would like to know.

The earth rotates around itself in one day, i.e. in 24 hours. If we imagine the earth's axis, it emerges at the north and south poles. If you were to stand at these two endpoints, then you would just turn around yourself.

It's quite different at the equator, the imaginary line that is furthest away from the two poles and divides the earth into two hemispheres. Anyone standing here covers over 40,000 kilometers a day. After all, that's 1,670 kilometers per hour.

To be precise: At the equator, the earth's radius is around 6,378 kilometers, so you get a circumference of around 40,075 kilometers and thus a speed of 1,670 kilometers per hour.

If you want to calculate the speed for a location other than the equator line, you simply have to multiply the value for the equator by the cosine of the latitude.

An example: Friedrichshafen on Lake Constance is 47.65 degrees north latitude, so that is 1,670 km / h times cos (47.65 °) = 1,125 kilometers per hour.

Just as the axis can fluctuate with a top, it is also the case with the earth. This egg is also called precession. Such a cycle lasts around 26,000 years. That is why the North Star will not stand in the north for all eternity. And this precession is also overlaid by another movement, the so-called nutation. It is caused by the moon.

On its orbit around the sun, the earth moves at an average speed of 29.78 kilometers per second, i.e. around 107,000 kilometers per hour. And the entire solar system rotates at around 220 kilometers per second, i.e. around one million km / h, around the center of our galaxy, the Milky Way.

So we're pretty much on the move, however, every roller coaster is a children's carousel!

Text: -jj- Image: NASA / Marvel / GFDL

Note: All images have been removed from the archive