[uizrizee] orbits partially explained

the fact that it is possible for a satellite to orbit the earth is unintuitive: what force keeps the satellite suspended in the sky?

"what goes up must come down" is good intuition if the earth is flat.  but the earth isn't flat: the direction of "down" changes depending on where you are.  if a projectile is moving horizontally so fast that its direction of "down" changes significantly over the course of its trajectory, then one can imagine that something more complicated than "what goes up must come down" might occur, and it does.

determinating exactly what does occur, for example, showing that a circular orbit is possible, requires more work, probably some actual math.  (actually, circular orbits are not possible with general relativity because of gravitational radiation.  an orbiting satellite therefore does not stay up forever, just as intuition originally suggested.  but calculating the inspiral requires a supercomputer.)