A satellite can be placed in an orbit 35786 km above Earth’s surface, and the satellite will be in motion at the same speed as the rotation of the Earth. As a result, the satellite will appear practically motionless when observed from the surface. Many communication satellites are placed in this orbit, and a satellite dish receiving signals from the satellite doesn’t have to track the satellite.
Flat-Earthers often take the fact that satellites are in motion and most satellite dishes have a fixed direction as ‘proof’ there’s something suspicious about satellites. They are wrong.
The lower the orbit of a satellite, the higher its orbital speed. And conversely, the higher the orbit, the lower the orbital speed.
From that relations, we can determine the orbital altitude where the angular speed matches that of the rotation of the Earth. The altitude is 35786 km above the surface of the Earth.
This orbit is called geostationary orbit. Any satellite placed in this orbit will have a fixed position relative to the surface of the Earth, as long as the satellite is above the equator and moves in the same direction as the Earth’s rotation.
Because a geostationary satellite appears motionless relative to Earth’s surface, a satellite dish can be directed to a fixed direction and does not have to track the satellite as long the satellite is still in the same orbit.
A geostationary satellite is always in an orbit above the equator. As a result, a satellite dish in the northern hemisphere needs to be pointed towards the south. And conversely, a satellite dish in the southern hemisphere needs to be pointed towards the north.
- Geostationary orbit – Wikipedia