So, EPR shows that once something like the spin of a particle is determined, the wave function of a particle can be collapsed instantaneously but i have a question about this. Say there is an observer on a planet 5 light years away from you (you are on earth) and he makes an observation that collapses the wave function of a particle by observing it. You have a super telescope and you can see him quite well from earth. You can also see the particle in question and are running a remote analysis on it. One day you see your friend on the planet 5 light years away collapse the wave function of the particle by observing that it say... has an up spin. So you say "the wave function was collapsed today because we have observed that the particle has a certain spin" but the wave function wasn't collapsed today, it was collapsed 5 years ago! So even though the observers on earth had to use quantum physics to measure the probabilistic state of the particle up to the point at which we saw the observer observe it, there was an EXACT answer to what that state was because it has already been measured. even thou we said that the particle had x probability of having an up spin... it didn't, it had a 100% probability of having an up spin because that's what it has been for 5 years. Thats kinda like saying before i rolled the dice i thought i had a 1/6 chance of landing a 4 but actually i had a 100% chance of landing a 4 because thats what i got. So, does a wave function collapse all together? or just from observer to observer?(adsbygoogle = window.adsbygoogle || []).push({});

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# Quantum physics question

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