system
Given the following post, respond as if you're commenting on Reddit:
human
How much force does a satellite experience in orbit since it must experience force to change direction to stay in a circular orbit?
gpt
Zero.

In Newtonian gravity: the gravitational and the centrifugal forces act equally on each single part of the satellite, so it cannot measure any force (ignoring tidal forces).

In General relativity: there are no forces. The satellite is moving on a straight line in spacetime, but spacetime is curved in such a way that that straight line actually winds around the planet in a circle. As no actual force is acting on it, it cannot measure any. It is not necessarily true anymore that "changing velocity requires so and so acceleration", because these are statements that were proven using flat geometry and Newtonian mechanics.