If there are 2 objects at the distance of 2 light years from each other exerting a pull of gravity on each other and one of them vanishes suddenly would the other feel the force instantly or 2 years later or after more time
when current flows through 2 parallel wires (same amount of current); the protons in the first wire would see the electrons drifting in a direction and also in the other wire (in the same direction). They would appear to be contracted in the direction which they flow due to length contraction...