Why wouldn't this work to send a message back in time?

There are two ways to answer this question: (1) from the perspective of Relativity, and (2) from the perspective of Quantum Mechanics.

From the perspective of Relativity, especially Special Relativity, assuming that quantum entanglement occurs at instantaneous speed, or at least some form of faster-than-light speed. If we were to send to a message an alien civilization many light years away, and they respond back using the same FTL method. But the point is that you're sending these message back and forth over long distances, so the communicators are not in the same spacetime frame as each other. The extent of time travel that you're doing is that you can find about an event happening in the remote frame before it actually appears in the local frame. You'll never be able to go back in time inside your own local frame, there will always be some passage of time in the local frame.

Now from the Quantum perspective, this was answered by Bell's Theorem, the simplified version of this is that spooky-action-at-a-distance can be explained away. If two seemingly correlated events appear to occur simultaneously, then chances are that there was a third unseen event that may have actually occurred in the past that went unnoticed, that actually set off both of these other two events off previously at less than or equal to the speed of light.

Why don't you prove it can. First of all you must have two particles that are quantumly tangled.

Move them to the locations before comunicstion start. The person in the link seemed to think the particles moved they are already entangled and the motion away has to be at sub light speeds unless they are photons.

This means they take time to travel .

The example given in the link was childish it assumed you know the money in the guys pocket before he leaves a better example is you grab the change off the counter while walking you see the beggar you reach in the pocket and toss a random amount in the beggars cup. Then you walk a distance and count your change since you didn't know the amount you started with you don't know how much you gave the beggar.

As soon as you measure a particle it's waveform collapses from my understanding. The waveform is more a theoretical thing to allow us to understand wwhat happens.

Basically it's your job to prove it works

Oh great snubber:

I used to be a biological scientist and then child advocate. Helped eradicate SMALLPOX... very real outcome! From this perspective, why would anyone want to retrograde information??/ To change current affairs? Make money?? Ahhhh...halt disease and pain? Interesting concept but flawed outcome...Huggles, Grandma Ellie

REALITY BEATS CONJECTURE ANYTIME!!