Wirebook › Glossary › Geostationary satellite
What is a geostationary satellite?
In one sentence: A satellite about 35,786 km above the equator that circles once a day, so it seems to hang still in the sky.
A little more
At 35,786 km above the equator, a satellite takes exactly one day to go round the Earth, the same time the Earth takes to spin. From the ground it seems to hang still, so a dish can point at it once and never move. TV satellites work this way.
The catch is distance. Even at the speed of light, going up and down again takes about a quarter of a second, so video calls and games feel laggy.
It's a bit like… A lantern on a very tall pole: easy to aim at because it never moves, but a long way to shout up to.