In sci-fi with “spinning” ships to make gravity, how does someone drop something and it lands at their feet?

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This fogs my brain every time I watch one of these shows and I feel like maybe I’m completely misunderstanding the physics.

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You’re in a “ring” ship. The ring spins. You’re standing on the inside of the ring so it takes you along with it, and the force created “pins” you to the floor, like a carnival ride. Ok, fine.

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But that’s not gravity, and it’s not “down”. Gravity is acceleration, so what keeps the acceleration going in the ring ship is that you are constantly changing your angular momentum because you’re going in a circle. Ok, so when you let go of something, like a cup or a book, wouldn’t it go flying towards the floor at an angle? If you jumped wouldn’t you look like you rotated a little before you hit the ground, because you’d, for that moment, be continuing the momentum of your angular velocity from when you left the floor and the room would continue on it’s new, ever turning, course?

Wouldn’t it kind of feel like walking “uphill” one direction and “downhill” the other, with things sliding about as the room “changed” direction constantly?

Am I just COMPLETELY missing this idea and creating a cause and effect that doesn’t exist?

In: Physics

25 Answers

Anonymous 0 Comments

No, your intuition is correct. In a rotating ring space station, a dropped object will not land at your feet. The object retains the “lateral” velocity it had at the radius you were holding it, which is less than the lateral velocity of the floor. So while it is falling, the floor (and your feet) moves sideways with respect to its path. To Your eyes, the falling path would be curved to the side.

Your next to last paragraph is also correct, in principal, but in practice I think the effect would be negligible. Your walking speed is much less than the speed of the ring, so the difference between walking one way vs the other would be tiny.

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