(shamelessly stolen from an imgur dump)

  • applebusch@lemmy.world
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    1 year ago

    I agree with your choices but your logic for the teleportation doesn’t hold up. You’ve assumed your momentum wouldn’t be conserved through the teleportation in a weird way. Assuming momentum is conserved, you would still fall just as quickly. In fact, you would reach terminal velocity in short order, and would have to continually teleport to keep yourself from crashing into the ground. By itself that would be bad enough, but you moving through the air between teleports would cause the air to move as well, so assuming you could keep up and hold your elevation, your velocity relative to the ground would increase to some number higher than terminal velocity. Think Chell continually falling through portals. Now you’re stuck unless you can also teleport slightly to the side without falling. Best case you go to one of those indoor skydiving places and get in so you can slow down without dying. I was going to explore what would happen if your momentum somehow wasn’t conserved, but that would imply some absolute fixed frame of reference or magical mumbo jumbo, neither of which exist.

    You could totally travel faster though, without even needing to walk. You would also be super dangerous in one on one combat sports. A well placed 7 inch teleportation can easily get the win in the right sports.

    • Atomic@sh.itjust.works
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      1 year ago

      I disagree with your teleportation assessment. Just as I don’t think my momentum would be conserved, you think it is. You have no more reason to believe it would than I have to believe it wouldn’t. Because there’s no foundation for teleportation as it doesn’t exist.

      I’m not sure what logic you want to use with something that is made up. But im gonna go ahead and assume my teleportation will work on my rules since no rules were ever specified.

      You can feel free to use whatever made up rules you want for your own magical power.

      • applebusch@lemmy.world
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        1 year ago

        Conservation of momentum is a law of nature, making it natural to assume it would still hold even with a hypothetical power. But you do you. It’s ok to be wrong sometimes.

        • ƬΉΣӨЯΣƬIKΣЯ@feddit.de
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          1 year ago

          conservation of momentum is only a true, when translational invariance holds. In addition, there may be a countless number of mechanisms by which teleportation changes a persons momentum. E.g. maybe the way this kind of teleportation works is Star Tek-like and your atoms get disassembled and reassembled, meaning they don’t need to have the same overall momentum, when whatever is doing the dissassembly stops atoms for dissassembly.

          • remotelove@lemmy.ca
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            1 year ago

            There are a ton of conditions that are left floating, for sure. Some people here are imagining this as “instant” teleportation. As in: here one second, there the next.

            If zero time passes when a person is teleported, that causes some problems. I like thinking about that one, TBH. That starts to dive into the realm of breaking space itself, which is super cool to noodle on. (Wormholes FTW!)

            My own questions would be more about how disassembly and reassembly would maintain original state. If an electron is moving when it is transported, where does that momentum go and how is it reapplied.

        • miss_brainfart@lemmy.ml
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          1 year ago

          But what if teleportation doesn’t move you from A to B, but just lets you disappear and reappear while you’re just standing there, so that there’s no momentum at all?

          • applebusch@lemmy.world
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            1 year ago

            No momentum at all relative to what? Relativity tells us that there is no fixed frame of reference. In practice what that means is there is no universal zero velocity. You only have velocity relative to other things. The implicit assumption in your argument is that you would have no momentum relative to the earth, which in itself is problematic. After all, the earth spins at a rate of 360 degrees per day, so not moving relative to the earth would mean moving 463.83 m/s relative to the surface of the earth at the equator, which is supersonic. But maybe you mean relative to the surface of the earth. What if you go to the moon? Or mars? Or into orbit? Maybe you mean relative to the nearest big thing. If you could somehow teleport from the ground into a plane, would the plane count as the nearest big thing? What about a bus? That’s on the ground, so maybe the nearest big thing would be the ground, if the mass of the thing matters in how the nearest big thing is determined. You can see how this can quickly turn into a mess of rules and special cases.

          • remotelove@lemmy.ca
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            1 year ago

            Where does the energy go if you are already moving when you teleport? Do you somehow lose all mass for a brief second? Instant transportation from point A to point B means that there is no in-between state to change the variables of nature. Zero time passes between being here one second and there the next.

            Most everything that has mass and is moving has momentum. If momentum were to somehow be cancelled, which it can’t be, your body would probably just stop completely. Even electrons have mass (9.1093837 × 10-31kg) and just stopping all electrical signals in your body at the same time seems like a bad thing. (I say “most everything”, because there are these strange things called photons. It doesn’t have mass, but has momentum. It’s also a particle (err… “energy packet”?) and a wave, which is even weirder.)

            Sure, we are taking about a completely fictional situation when it comes to teleporting so this conversation is just really just a thought experiment.

            If you were granted any wish, but you only received an extremely literal version of that wish, what are the consequences? That is humorous to think about, actually.

            • miss_brainfart@lemmy.ml
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              1 year ago

              Where does the energy go if you are already moving when you teleport?

              If you are in fact moving, there’d be momentum, like you say. But if you don’t? If you just sit there, and teleport from one comfy armchair into another, not changing anything about your position?

              • MightyGalhupo@lemmy.world
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                1 year ago

                Well you see, there’s also the problem that if you teleported and it got rid of your momentum, unless something immediately speeds you back up to the speed of the earth, it will just woosh past you. Even if something like the air sped you up, while it’s speeding you up, the friction would likely tear you apart.

              • remotelove@lemmy.ca
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                1 year ago

                That goes back to my point about the humble electron.

                There are a ton of things moving in your body all the time regardless if you are sitting still of not. The only thing that I can think of that would be drastically impacted by instant cancellation of momentum is electrical signals. I admit, that is absolutely pushing the boundaries of what I know about physics at that scale.

                Stopping every electrical signal in your body simultaneously and assuming it will just resume spontaneously seems odd to me, is all.

    • remotelove@lemmy.ca
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      1 year ago

      I love the thought experiment. However, what really makes me think is how air behaves.

      Would the air from the destination get teleported back to fill the void that you left? Does the person just displace the air at the destination when they teleport?

      What really gets me curious is what would happen during several quick teleports if the air is just displaced at the destination. Regardless, there would be an extreme vacuum at the starting location for a very short period of time. There was no specific time given about how long a person needs to wait between jumps, so you could leave a heck of a trail of destruction in your wake.

      Some air would be displaced backwards after the teleport decreasing the volume of the void, but a void would still be there.

      Would the forces be strong enough to suck the person backwards? Would the atmosphere simply collapse the void creating a bit of thunder and heat?

      I can’t even fathom what happens to time. If you teleport instantly, that may imply that you are traveling faster than the speed of light. The universe implodes?

      • applebusch@lemmy.world
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        1 year ago

        We can make some estimates for what would happen. The specific enthalpy (basically energy per kilogram) of air, modeled as a diatomic ideal gas, would be 7/2RsT, where Rs is the specific gas constant of air and T is the temperature. The specific gas constant of air is 287.05 J/(kg K), so at 293.15 Kelvin (20 C, ~70 F) the air would have 294kJ per kilogram. An average human displaces about 0.06522 cubic meters (65.22 Liters, 17.2 gallons), and air at standard conditions has a density of 1.20 kg/m^3, meaning you displace about 0.078 kg. This means an average person teleporting would create an energy difference of about 23kJ between the vacuum they leave behind and the surrounding air. That’s as much energy as a 1kg mass moving at 214 m/s (478 mph, 770 kph) or about Mach 0.62 at sea level, or a 1000 kg mass moving at 6.78 m/s (15 mph, 24.4 kph). So imagine getting crushed against a wall by Grandma driving a small sedan at a human running speed, except the wall doesn’t take any of it. That is also a bit more energy than a .50 BMG bullet, which apparently is used to shoot down helicopters.

        If you teleport really close to your starting position, we can assume the total energy would be doubled. Also consider that this analysis is conservative. The faster the teleportation happens the more energy you’re going to release. This only accounted for the energy of the air itself, not the kinetic energy of all the air that would rush in to fill the vacuum, or the energy you add to the air when you pop back in, which could be significantly more if you pop back in really fast. So it could be quite a bit of energy. I always imagined that a superhero or villain that could teleport would need some kind of force field just to survive the process, and that they could develop their ability to teleport faster to use it as a weapon, or teleport slower for stealth and not destroying their destination. Looking back at Jumper the amount of damage they do when they teleport is pretty minor, considering the math. The energy released would only grow if you could take stuff with you.

        • remotelove@lemmy.ca
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          1 year ago

          Thanks for doing the leg work on that one! I honestly didn’t know where to start, but I knew there was a ton of energy involved.

      • BeardedGingerWonder@feddit.uk
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        1 year ago

        You know when you see people teleport on TV and they just appear in a different place with no major world breaking repercussions? It works like that

        • remotelove@lemmy.ca
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          1 year ago

          Sure. But that is boring. The magic of TV does a poor job of taking fictional situations and showing how things work in real life. Real life can be much more dramatic and interesting. (Or much less dramatic and interesting, in some cases. Like car explosions.)