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

The closer you are to Earth, the faster you have to orbit to stay in orbit. For example, the International Space Station is only 254 miles away, so it has to orbit really fast (about 90 orbits per day) to stay in orbit.

The further you are from Earth, the slower you have to orbit to stay in orbit. The moon is about 240,000 miles away from Earth, so it has to orbit really slow (about one orbit every 27 days) to stay in orbit.

It stands to reason that there is a distance somewhere between those to where you will have one orbit every one day. That distance turns out to be about 22,360 miles, which as you guessed is somewhere between the close-fast orbit of the ISS and the far-slow orbit of the moon.