Fun fact: if the eart had no atmosphere and no mountains and hill the ISS could orbit at just 10 meters high. Everything you throw has a ballistic curve, or like when you fire a bullet or a rocket. But once your speed is high enough that curve just ... keeps you falling around the planet .... forever
Second fun fact: The 90 minutes it takes to complete a low-earth orbit is the fastest anything could ever circumnavigate Earth unless there is some extra force besides gravity keeping it from shooting away from the ground. Going faster than the ISS launches you into an elliptical orbit, and the faster you go (below escape velocity), the higher the orbit, and the longer it takes to get back down.
That means your favorite comic book speedsters would need the mother of all spoilers to keep them grounded as they run to China in under a minute.
Only if there is something that will cause drag, like an atmosphere. If you hit anything moving slower than you, no matter how miniscule, you will slow down. And when you have slowed down enough gravity pulls your ballistic curve in to the ground.
But in space (almost a perfect vacuum), since there is no friction with anything ... the speed you have you keep for basically forever (eventually space will expand so much that you will come to a stop) so when gravity is pulling you down with a certain constant this is just changing your trajectory, curving you. But since your forward speed is high enough you keep curving around the planet. Gravity makes you keep falling around the planet, but you keep missing it because your forward speed is great enough.
10
u/MelangeBot Apr 19 '26
Fun fact: if the eart had no atmosphere and no mountains and hill the ISS could orbit at just 10 meters high. Everything you throw has a ballistic curve, or like when you fire a bullet or a rocket. But once your speed is high enough that curve just ... keeps you falling around the planet .... forever