2
votes
3answers
136 views

What is the cause the light is affected by gravity? [duplicate]

I know that photons have no mass and that a photons exist only moving at the speed of light. So what is the cause that a massive astronomical object can bend a ray of light? I have two thoughts, but I ...
2
votes
2answers
209 views

Interaction speed between electric charges and magnetic materials

Einstein said that the speed of a matter in universe cannot exceed the speed of light. Is it correct for electric force transmission speed from one electric charge to other one? What is ...