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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[–] 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.

[–] Buddahriffic@lemmy.world 2 points 1 week ago

Neither do the two gravity wells the stick spans. And the earth and moon are moving relative to each other, someone would probably get their head knocked off by that stick. Before it eventually falls to the earth with quite a bit of force because earth's gravity well will win. Then it'll eventually settle into a giant teeter totter, assuming it is rigid enough to survive the impact.

[–] 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.

[–] Ludrol@szmer.info 2 points 1 week ago
[–] WorldsDumbestMan@lemmy.today 2 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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[–] Pulptastic@midwest.social 2 points 1 week ago

Your push would travel at the speed of sound in the stick. You could think of hitting a pipe with a hammer, the sound of the hit would travel at the speed of sound, same is true for you pushing the stick.

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

Because you put the apostrophe in the wrong place?

[–] ILikeBoobies@lemmy.ca 1 points 1 week ago

Move a sheet up and down rapidly

You can see the wave travel across it

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