Physicist: This subtlety was one of the great insights of Newton; that the “falling apples” force and the “circling planets” force are one and the same.
Newton's original thought experiment describing the parallels between falling and orbiting. The faster an object moves sideways the longer it stays aloft. Fast enough, and it never hits the ground at all.
Whether gravity pulls an object into orbit or just “makes it fall” depends on how the object is moving. Basically, every object wants to follow some kind of orbital path. If you toss a ball, even that ball is following an orbital path. If that path happens to intersect the ground, then we say “the object fell”. If that path doesn’t intersect the ground, then we say it’s in orbit.
Anytime an object is in free-fall it's following an orbital path. Gravitationally speaking, until a thing hits the ground it can't tell the difference between the Earth and an Earth's worth of mass crammed into a point (black X).
When in free-fall, all that the ball “knows” is that there’s some gravity around. When it hits the ground it’s as surprised as anything else. The path that any tossed or falling object follows is just the tip of a very elliptical orbital path that, if the Earth’s mass were all crammed together in a point, would eventually bring the object back. Unless you were to throw the ball at a couple thousand mph, it would take about half an hour to complete the loop.
So the only difference between a satellite falling back to Earth and staying in orbit is whether or not the satellite’s orbital path intersects the surface of the Earth. So, Douglas Adams was right; “Flying is simple. You just throw yourself at the ground and miss.”
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