[El Gato]

“For example, if the first one is measured and collapses into the up state, the second one will instantly collapse into the down state, even if it’s light-years away.”

Which is one of the reasons Einstein called it "Spooky". The "communications" happen "instantaneously", IOW, faster than the speed of light.

Understanding this on a deeper level might have all sorts of "interesting" consequences and applications.

[steve86]

I’ve always thought the two entangled, separated particles are adjacent in some higher dimension, or even occupy the same space in the higher dim, making speed of light constraints moot. But I don’t have the quantitative IQ to even start on a mathematical exploration of the concept.

[UCANSEE2]

The "communications" happen "instantaneously", IOW, faster than the speed of light.

Is it really 'communication'?

Or is it the result of matched sets which must maintain a balance?

Like a teeter-totter. If one pushes down on the seat, the other seat, around eight feet away, instantaneously goes up.

The mystery, to us, is the pipe in the middle.

[UCANSEE2]

Which is one of the reasons Einstein called it "Spooky".

It should be regarded as a quantum-style conservation law, in this case conservation of spin angular momentum. (teeter-totter)