5 ms·

The thing is, instantaneous communications do not and can not exist in our universe. In fact, there is no such thing as two things happening "at the same time"

The thing is, instantaneous communications do not and can not exist in our universe. In fact, there is no such thing as two things happening "at the same time" if they are in different locations. If you observe two things happening at the same time from where you are standing (say, you are see two stars exploding at the same time and you know they are both at the exact same distance from you, so you know light took the same amount of time to reach you), another person who was passing you at high speed at the same time will say that you are actually wrong, those two stars exploded at completely different times, after doing the exact same measurement as you. We talk about the "speed of light" being a constant, but this is misleading. The "speed of light" is actually the "speed of causality". Breaking the speed of light, with some theoretical instant communication, would be breaking causality. In the earlier example, if those two stars each had an emergency beacon that sent you an instant message just as they exploded, you would receive both simultaneously. But the person travelling past you would be very confused about how that could happen, since he clearly observed them exploding at different times.

dumpsterdiver 6y ago
> The thing is, instantaneous communications do not and can not exist in our universe. In fact, there is no such thing as two things happening "at the same time" if they are in different locations. I do understand what you're saying, and while I agree that observations differ based on the location of the observers, there's one thing that still baffles me. Quantum entanglement. Let's say that we replace the wizards in my example with a pair of entangled particles, and in fact, for this thought experiment let's pretend that humans and "observers" don't even exist anymore - there is noone left in the universe to observe what is happening anywhere. Wouldn't our current understanding state that the wave function would be identical between the particles regardless of where those particles are located in spacetime? In effect, wouldn't the wavefunction be "happening at the same time"? Mind you, I'm not suggesting that the particles are communicating, simply that their waveforms are identical. It's really baffling to me that one particle could be in an area subjected to massive gravitational distortion while the other is not (a completely different world line), and yet they are always in sync. Thoughts?
- user-the-name 6y ago
  It is a deeply weird thing and we do not have a theory yet to explain this satisfactorily, but the one thing we do know is that no information can actually be transmitted this way, so it does not break the speed of causality.
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  - dumpsterdiver 6y ago
    > It is a deeply weird thing and we do not have a theory yet to explain this satisfactorily, but the one thing we do know is that no information can actually be transmitted this way, so it does not break the speed of causality. I've read that as well, and I concur that popular opinion states that quantumly linked particles do not appear to violate causality, because we don't believe they are actually communicating at all, let alone communicating faster than light. The way I interpreted this claim is that those particals are more akin to a deterministic algorithm, which is to say, once you set it free it will always result in the same answer based on the seed. I'm still very confused though about how those particles could remain in sync in vastly different spacetimes. That to me, is a flaw in the conjecture, and one that cannot be tested. We've based our understanding of quantum entanglement only upon that which we can observe, and so we truly don't know if a quantumly entangled particle will be "behind" if it is in a denser gravitational field. It's unprovable, because even if we were to travel into that spacetime, we could not escape to share the results with other observers. Thank you again for your input. Your argument forced me to mentally reconcile "observable reality" from "actual reality", and that was a fun and intriguing thought experiment, albiet probably pointless since none of it can be proven. Our observations do not define reality, they only measure it to the best of our ability. And most of the time when we measure reality, apparently we fuck it up (i.e. breaking quantum links, or just having incorrect assumptions).

dumpsterdiver 6y ago

> The thing is, instantaneous communications do not and can not exist in our universe. In fact, there is no such thing as two things happening "at the same time" if they are in different locations. I do understand what you're saying, and while I agree that observations differ based on the location of the observers, there's one thing that still baffles me. Quantum entanglement. Let's say that we replace the wizards in my example with a pair of entangled particles, and in fact, for this thought experiment let's pretend that humans and "observers" don't even exist anymore - there is noone left in the universe to observe what is happening anywhere. Wouldn't our current understanding state that the wave function would be identical between the particles regardless of where those particles are located in spacetime? In effect, wouldn't the wavefunction be "happening at the same time"? Mind you, I'm not suggesting that the particles are communicating, simply that their waveforms are identical. It's really baffling to me that one particle could be in an area subjected to massive gravitational distortion while the other is not (a completely different world line), and yet they are always in sync. Thoughts?

user-the-name 6y ago
It is a deeply weird thing and we do not have a theory yet to explain this satisfactorily, but the one thing we do know is that no information can actually be transmitted this way, so it does not break the speed of causality.
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- dumpsterdiver 6y ago
  > It is a deeply weird thing and we do not have a theory yet to explain this satisfactorily, but the one thing we do know is that no information can actually be transmitted this way, so it does not break the speed of causality. I've read that as well, and I concur that popular opinion states that quantumly linked particles do not appear to violate causality, because we don't believe they are actually communicating at all, let alone communicating faster than light. The way I interpreted this claim is that those particals are more akin to a deterministic algorithm, which is to say, once you set it free it will always result in the same answer based on the seed. I'm still very confused though about how those particles could remain in sync in vastly different spacetimes. That to me, is a flaw in the conjecture, and one that cannot be tested. We've based our understanding of quantum entanglement only upon that which we can observe, and so we truly don't know if a quantumly entangled particle will be "behind" if it is in a denser gravitational field. It's unprovable, because even if we were to travel into that spacetime, we could not escape to share the results with other observers. Thank you again for your input. Your argument forced me to mentally reconcile "observable reality" from "actual reality", and that was a fun and intriguing thought experiment, albiet probably pointless since none of it can be proven. Our observations do not define reality, they only measure it to the best of our ability. And most of the time when we measure reality, apparently we fuck it up (i.e. breaking quantum links, or just having incorrect assumptions).