Why would'nt this work?
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It would stretch like a rubber band stretches just a lot less. Wood, metal, whatever is slightly flexible. The stick would either get slightly thinner or slightly less dense as you pulled it. Also, you won't be able to pull it much because there's so much stick.
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Seems likely. The most rigid materially known, (or at least theorized) is nuclear pasta.. Nuclear pasta only forms inside neutron stars, stellar objects that are the last stage of matter before matter gives up entirely and collapses into a black hole.
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Very well put.
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You're not creating more stick, but you're making the stick longer. The pressure wave in the stick will travel at the speed of sound in the stick which will be faster than sound in air, but orders of magnitude slower than light.
Everything has some elasticity. Rigidity is an illusion . Things that feel rigid to us are rigid in human terms only.
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How does that work?
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I get it. Elasticity isn't something you think about in the every day so it all seems rigid.
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This is hard to truly eli5, so I'll have a go too, in case the others haven't cleared it up for you.
The spot on the moon that moves isn't a real thing, it's the effect of photons hitting the left side, then other photons hitting the right side. The 'reason' or 'cause' for those photons comes from earth very much at light speed. But the left side of the moon can't cause an effect in the right side, that fast. It just experiences a thing right before the right side experiences something similar.
Like if two cars drive from London to Manchester and Liverpool, arriving within seconds of each other. It doesn't mean you can drive from Manchester to Liverpool in seconds.
There's an SMBC I love on this: "The shadows of reality go as fast as they like." https://www.smbc-comics.com/comic/superluminal
Bonus: IIRC, any two events that are too close in time for light to travel from one to the other, can be viewed from a different "inertial reference frame" (someone else moving fast and analysing things with the same physics) as being the other way round. I.e. the right observer could see the right hand side of the moon get lit up before the left hand side. But the chap on earth wiggling the laser pointer is still wiggling it slower than the speed of light, so this observer would still see the laser pointer move from left to right. How does that work?
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Autocorrected from unfoldable. This is what I get for occasionally browsing on a shitty Amazon tablet. At least it was cheap to the point of being almost free.
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Also, even if you could somehow pull the stick, Newton’s Second Law (F = ma) tells us that the force required to move it depends on its mass and desired acceleration. If the stick were made of steel with a 1 cm radius, it would have a mass of approximately 754x10^6kg due to its enormous length. Now, if you tried to give it just a tiny acceleration of 0.01 m/s² (barely noticeable movement), the required force would be:
F = (754×10^6) × (0.01) = 7.54×10^6 N
That’s 7.54 MN, equivalent to the thrust of a Saturn V rocket, just to make it move at all! And that’s not even considering internal stresses, gravity differences, or the fact that the force wouldn’t propagate instantly through the stick.
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As it so happens the way the atoms push each other is electromagnetism, in other words sending photons (same thing light is made of) to each other but these photons are not at visible wavelengths so you don't see them as light.
Wat? I strongly believe you are not correct. Which is to say, I think you are talking out of your arse entirely. If you push on a thing you peturb the electron structure of the material. These peturbations propagate as vibratory modes modeled as phonons.
While technically some of this energy is emitted as thermal radiation that is not primarily where it goes.
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There are multiple forces at work in a rocket nozzle:
- The exhaust is pushed outward, giving the rocket thrust
- The exhaust hits the wall of the nozzle as it gets thinner, braking the rocket
These two effectively cancel out, which is why the actual effect of making the nozzle thinner/converge is that it increases the back pressure within the engine (constricted space, smaller hole), essentially (idk how) increasing the efficiency of the fuel burning.
However, when the nozzle gets too thin, the exhaust becomes faster than its speed of sound. Since the pressure travels at the speed of sound, it can now not actually get back into the engine anymore. So that's the limit of how thin you can make the nozzle. The pressure has to get back into the engine to have its effect, so you can't make the exhaust travel faster than its speed of sound.
If any of this sounds wrong to anyone, let me know, I'm not an expert in this.
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Nah, I prefer using quantum spookiness for that. Send a steady stream of entangled particles to the other person on the moon first. Any time you do something to the particles on Earth, the ones on the Moon are affected also. The catch is that this disentangles them, so you have only a few limited uses. This is why you want a constant stream of them being entangled.
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My mistake, that's why sound travels at the speed of light.
It's just not useful to talk about this at the level of the standard model. We are interested in the bulk behaviour of condensed matter, the fact of the matter is that you will not be able to tell that the other end of the stick has been touched until the pressure wave reaches the end. It doesn't matter if individual force carriers are moving at the speed of light because they are not moving in a single straight line. You are interest in the net velocity.
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Exactly. At the atomic level solid matter acts a lot like jello. It also helps explain why things tend to break if you push or pull on them at rates that exceed the speed of sound in that material.
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This wouldn't work, entangled particles don't work like that. They would be disentangled the moment you do anything to either particle of the entangled pair. The only time any information can be encoded onto entangled particles is when they're created.
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I very explicitly said the whole thing is slower than the speed of light (much slower even) and even pointed out why: at the most basic of levels, the way charged particles push each other without contact is the electromagnetic force, meaning photons, but the actual particles still have to move and unlike photons they do have mass so the result is way slower than the speed of light.
To disprove the idea that a push on a solid object can travel faster than the speed of light (which is what the OP put forward), pointing out that at its most basic level the whole thing relies on actually photons which traveling at the speed of light, will do it.
Going down into the complexity of the actual process, whilst interesting, isn't going to answer the OPs question in an accessible and reasonably short manner using language that most people can understand.
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The only time any information can be encoded onto entangled particles is when they’re created.
If that were the case, then we aren't really doing FTL communication, unless we manage to entangle them at a distance. No?
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- Aceticon BcS Applied Bullshit
