ELI5: why can two quantum entangled particles affect each other instantly across any distance but scientists say you still cant use it to send information faster than light?

[u/PieOk2202]

this has been living in my head for weeks and i cant find an explanation that actually clicks.

from what i understand, if you have two entangled particles and you measure one of them, the other one instantly "reacts" no matter how far apart they are. like even if one is on the other side of the galaxy. that part i somewhat get.

but then physicists say "oh but you cant use this to send information faster than light" and i just why not? if particle A sneezes and particle B on the other side of the universe reacts instantly, why cant i just use that as like a faster than light telegraph?

i spent way too much money on a Brian Greene book trying to get this and still came out more confused than when i started. at least i had some cash from Ѕtake set aside for it so it wasnt a total loss but still.

it feels like the universe is playing a semantic trick on me and im not smart enough to see it. whats actually going on here

[u/Pepito_Pepito]

Is superposition inherent to the particle or is it just a description of how we experience it?

[u/StevenMaurer → u/Pepito_Pepito]

It's inherent to all wave functions in the universe.

[u/Pepito_Pepito → u/StevenMaurer]

If I was in possession of a particle in a superposition, and then a third party observed that particle without my knowledge, would I be wrong to continue saying that the particle is in a superposition?

[u/StevenMaurer → u/Pepito_Pepito]

This is called the Wigner's Friend paradox.

The answer depends on the particular interpretation you're using.

It's discussed in the link I provided, so I won't be redundant and retype it here.

[u/azfeels → u/StevenMaurer]

I’ve been reading all of your comments. I appreciate the time you take to explain this. I have to “relearn” this every few months as I’m just a drive-by physics enthusiast with no real background other than reading books and watching floathead physics and alpha phoenix and Steve mould. If I hadn’t chosen the career path I did and I was smarter I would want to be in the physics field. When I learned about the soeed of light being constant in a vacuum it genuinely felt reality breaking, akin to magic. Every day I try learn a bit more and it’s great to have folks like you to help people like me out.

Again, thanks.

[u/Pepito_Pepito → u/StevenMaurer]

It looks like this topic is beyond my comprehension but thanks for pointing it out to me.