Re: Better
So! Entanglement is not faster than light in that there is no "travelling" happening between the two particles. Two entangled particles have a shared quantum state, which is broken as soon as one particle interacts with any other particle or field. Until then both particles exist in both/all states simultaneously. Once interacted, the spin of one particle immediately implies the opposite spin in the other - the quantum state is determined instantaneously. The act of measuring the spin also counts as an interaction and would thus break the entanglement. It cannot thus be used for any meaningful superluminal communication. There is no time travel, it's just how quantum physics works, but casualty is always preserved.
As for spin, the atomic particles do not actually spin. At the subatomic level, charged particles (electrons and protons) act like tiny little magnets. Since magnetism appears when a charged particle is moving, it baffled scientists that a charged particle not moving much could have such a strong magnetic field. Back in the old days, they assumed that the particles were solid and spinning, and it was this spin creating the magnetic field. However with the advent of quantum physics, it became clear that the particles were not actually spinning as they're not solid but instead point-like particles (the quarks are, protons are not as they're made up by quarks). The name spin stuck, but really in simple terms, it would be called "intrinsic magnetism". This "spin" exists only in certain states, so unlike a magnet it's, as you'd expect in Quantum physics, "quantized".
