A geosynchronous orbit (GEO) is a prograde, low inclination orbit about Earth having a period of 23 hours 56 minutes 4 seconds. A spacecraft in geosynchronous orbit appears to remain above Earth at a constant longitude, although it may seem to wander north and south.

What forces act on a geosynchronous orbit?

Earth's gravity & centrifugal forces act on geostationary satellites.

What is the opposite of a geosynchronous orbit?

While geosynchronous orbits match the rotation of Earth (24 hours), semi-synchronous orbits take 12 hours to complete an orbit. Instead of 35,786 kilometers above the Earth's surface, semi-synchronous orbits are approximately 20,200 kilometers above the surface.