## Uniform Circular Motion

The motion of a specific location on Earth due to Earth’s rotation is a uniform circular motion. We can separate it into a uniform linear motion and a centripetal acceleration toward Earth’s center. From the reference frame of an observer on Earth, the latter results in a constant centrifugal acceleration, which is felt simultaneously with Earth’s gravitational acceleration.

We often use the uniform linear motion of everyday objects to explain the effect (or the lack of thereof) of uniform motion of Earth’s rotation. Flat-Earthers incorrectly reject it just because “it is not a circular motion unlike Earth’s rotation” In reality, a uniform linear motion is one component of a uniform circular motion. And these explanations are correct and still apply.

## Earth’s Rotation in Videos Taken From Space

The Earth rotates only once every 24 hours. To notice the rotation of Earth in a video taken from space, we need to speed up the video so that it appears fast enough for us to notice it. We also need to make sure the video was taken from a spacecraft where its motion does not dominate over the movement of Earth itself.

Flat-Earthers claim that videos taken from space were faked because the Earth does not appear rotating. In reality, Earth rotates far too slowly to be casually seen without increasing the speed.