An apparent force arising from the fact that Earth turns on its axis. It is an apparent force that makes sense only because Earth is a noninertial frame of reference. Earth's spinning creates a constant centrifugal acceleration in which objects appear to curve because Earth is spherical, with different points on the surface spinning at different speeds. If, instead of being a spherical, rotating planet, Earth were flat, there would be no Coriolis force because all points would spin at the same speed.