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

Imagine a yoyo. Now instead of yoyoing, you twirl it above your head like a lasso. The yoyo is the satellite, the string represents gravity, and your finger is Earth. Now if you do the same with a shorter string, the yoyo spins faster. If you were to make the string longer, the yoyo spins slower. Same thing happens with satellites. Those in lower orbits, closer to Earth, orbit quickly. Those further out orbit slower. Geosynchronous orbit is the orbit where a satellite takes exactly one sidereal day to spin around once, and a geostationary orbit is a geosynchronous orbit aligned with the equator. Now because Earth revolves once on its axis in a sidereal day, it and the satellite appear to stay in a straight line even though they’re actually spinning around. If you go above a geosynchronous orbit, the satellite actually appears to move backwards!