An object falling straight downward will be slightly deflected due to Earth’s rotation. It is the Coriolis effect that arises from the vertical motion of the object. Several experiments have confirmed it since the 18th century.
Flat-Earthers claim that we cannot observe the deflection from falling objects, and they use it as “evidence” that Earth is stationary. In reality, it is possible to detect and measure the deflection with careful observation and a significant height, but the amount of deflection is too small in everyday scenarios.
- Fallexperimente zum Nachweis der Erdrotation – Wikipedia