eli5: I’ve heard orbit described as continuously falling past or missing the Earth, how then do objects in geosynchronous orbit above a single point not fall out of the sky?

Question

eli5: I’ve heard orbit described as continuously falling past or missing the Earth, how then do objects in geosynchronous orbit above a single point not fall out of the sky?

In: 2204

Answer 1

[Relevant xkcd](https://what-if.xkcd.com/58/)

The short version is that the earth is spinning too. There’s a distance from the earth where you can be going fast enough sideways to “miss” the earth when falling, i.e., be in orbit, but be moving at the same speed the earth is turning at. It’s pretty far out actually.

We call that distance “Geosynchronous Orbit”, since things in that position, moving sideways like that end up appearing to stay directly above the same point on the planet.

There is, of course, a much longer version, and it has to do with the satellite’s orbital velocity synchronizing with the gravitational force of the earth such that there’s an apparent relationship between a spot on the ground and the satellite, but it involves a lot of math, and is probably better understood by playing Kerbal Space Program.