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?
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Imagine you’re holding one end of a rope, and there’s a ball attached to the other end. If you swing that ball around on the rope, it will move in a circle around you, with a radius equal to the taut length of the rope.
The reason for this is that the tension in the rope is constantly pulling the ball towards you. But the ball is already moving sideways relative to where you’re standing, so the ball doesn’t come straight towards you. Instead, it starts moving in another direction until the tension in the rope acts on it again, to the same effect. This creates a circular motion that continues for as long as the speed of the ball and the tension of the rope remain the same.
In this analogy, you are the Earth, the ball is a satellite, and the tension in the rope is the force of gravity (equivalent to the weight of the satellite). So as long as a satellite maintains a certain speed and doesn’t lose any mass, it will maintain a circular path around the Earth. The tricky part of setting up an orbit is getting the satellite up to the necessary speed for its weight.
Hope that helps! Let me know if you’re still confused by anything.
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