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
You are correct, it doesn’t fall ‘straight down’, it falls ‘sideways’ depending on the direction of spin. This has some very interesting effects that are typically not explored in, say, sci-fi shooter-type games where simple up-down ballistics shouldn’t be. If you’re lucky someone puts in something like “Warning: objects fall towards window in this area.” as a sign. The Expanse is a masterpiece because they do account for it and show it on screen. Babylon 5 has references and shows it in spaceship combat but not usually inside the station itself. The Battlestar Galactica remake is somewhere in the same range.
It gets better, or worse, when you think about it.
If you’re rollerblading in one direction in the ring, you’ll experience less and less “gravity”, until finally you’ve cancelled out the speed, and are now in freefall.
Go the other way around the ring, and your effective weight doubles!.
It would be a terrible environment for parkour, too. The place you’re trying to land would move away before you arrive.
The big issue here is the *radius* of the ring. If it is too small, then not only will dropped objects curve away, but walking around the thing will be next to impossible without throwing up or falling over. There will be a very noticeable gravity gradient between your feet and your head.
If the ring is big enough, these effects will be too slight to notice, and a dropped object will fall in what *appears to be* a reasonably straight line in your frame of reference. Measure it with a laser or something, you can maybe see a slight curve. It would take a radius of at least 100 meters for humans to effectively walk around inside it with no ill effects.
And another thing about SF spaceships: they frequently show a [ship that has a rotating part and a stationary part.](https://www.sharecg.com/images/original/164592.jpg) This will not work, at least not without constantly expending energy. The reason is because the “stationary” part is not anchored to anything, so it will just counter-rotate (same thing that happens to a helicopter if it loses its tail rotor).
The spinning motion causes everything to want to fly away and as a result, the inertia of ‘flying away’ simulates gravity when you can’t and have a surface under you.
Yes, all those things would happen. To mitigate them, you have to use a bigger ring. In something like the ship from 2001, the effect would be noticeable. In something with a half kilometer or so radius, you could do an experiment in your home to measure the effect. Beyond a few kilometers radius, it gets hard enough to detect that you’d need lab equipment. You definitely wouldn’t notice it day-to-day.
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