this post was submitted on 11 Feb 2025
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It can look dumb, but I always had this question as a kid, what physical principles would prevent this?

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That would not work. Pushing an object is transmitting kinetic energy to it. The object will push back, and energy would not be distributed to the whole object at the same time.
If the object cannot be altered in any way, then the energy would not be transferred to it, and if it has enough plasticity to absorb the kinetic energy, it would be spread in a wave to the tip. A wave that would always be slower than light.

Now stop fooling around and give Ruyi Jingu Bang back to Sun Wukong.

[–] ladicius@lemmy.world 2 points 1 week ago (1 children)

What about the mass of that stick? Inertial doesn't care for your little silly games.

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[–] tias@discuss.tchncs.de 2 points 1 week ago* (last edited 1 week ago)

I don't see this mentioned in any of the other comments: the repulsion between atoms that causes the movement to propagate through the stick is actually communicated via photons. So your push really generates the same kind of particles that your light torch is generating, and they travel at the same speed. Except in the stick it is slowed down by repeated absorption and excitation by the electrons of the atoms.

[–] nomoredrama@lemmy.world 1 points 1 week ago

Because you put the apostrophe in the wrong place?

why wouldn't this work

because bullets are faster than whatever the fuck speed stickman is achieving
and even bullets are slower than light

[–] Jhex@lemmy.world 1 points 1 week ago
[–] WorldsDumbestMan@lemmy.today 1 points 1 week ago (3 children)

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.

[–] InputZero@lemmy.world 2 points 1 week ago (1 children)

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.

[–] ulterno@programming.dev 2 points 1 week ago* (last edited 1 week ago)

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?

OIC, it's still useful if we want to make a secret key and send it somewhere. Then both sides can take a reading sometime in the future and they can then use whatever cluster of entangled particles they saw, as the symmetric key.

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[–] Hupf@feddit.org 1 points 1 week ago
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