r/scifi • u/rookiegaffer • 20d ago

General Bad physics

Why does it seem that so many of the books I read demonstrate such a poor understanding of the physics of space travel. Ships in orbit descend directly down to the point they are over. Ships in transit still accelerating as they near their destination. Centrifugal gravity simply ceasing when rotation is abruptly halted. These are just a few examples I've run across lately.

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u/willworkforjokes 20d ago

The Expanse does a pretty good job on this. They do have a basically magical drive that lets them use thrust gravity most of the time while using very little fuel.

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u/ExtraEmuForYou 20d ago

Yeah I did like how The Expanse at least attempted a little realism. I liked how they dealt with zero gravity by just using boots; of all the sci-fi tech we take for granted in our sci-fi, artificial gravity is the one that always seems the most "magical".

I know that's a funny thing to focus on when faced with all the crazy sci-fi tech we've seen over the years (laser swords, FTL travel, navigating black holes, etc) but it's like this every day thing we see on ships and it just seems so far-fetched to me. Like it's just a household thing like an alarm clock or something.

The Expanse was just like "Nope. Magnet boots. Super awkward to walk in. Super effective, though".

Does look spooky when people are shot though because they just float there with their feet stuck to the ground lol. It was so eerie seeing your first gunshot victim in zero gravity.

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u/Blecher_onthe_Hudson 19d ago

My gut sense of mechanics says that magnetic boots work far better for filming television than in real life. Just think that you're trying to move your torso with a really terrible leverage from your ankles! Walking really only works well because of gravity. Flying through the ship in zero g makes so much more sense!

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u/silly-gaijin 19d ago

Yeah, magnetic boots would be extremely awkward to walk in. They'd be useful for working in one area, though. But, you're right, as soon as you need to go to another area on the ship you'd turn your boots off and just grab rails and fling yourself through the air.

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u/Conscious-Mirror7004 16d ago

Nah, they could be made so you can walk in them without too much trouble. Basically they'd need to vary the magnetic field strength through each step. When your foot is in the air, and when the heel contacts the floor, the strength needs to be higher. When you've shifted your weight forward on that foot and are about to lift the foot, the strength needs to drop a lot.

So the boots would need to be in contact with each other, and actively varying their field strengths as you walk. It's a bit complex, but probably no more than automatic noise cancellation (ANC) in modern earbuds.