Here are things we get to know from theory of relativity:
1) Empty space (Vacuum) is not actually empty, it is active. Space is 3 dimensional Fabric, which can bend, vibrate, interact.
2) When you keep some heavy object (Sun) on that fabric, you bend this fabric and this causes gravity. Just as a marble starts revolving when thrown in to a bowl, planets revolve around the Sun.
1) Empty space (Vacuum) is not actually empty, it is active. Space is 3 dimensional Fabric, which can bend, vibrate, interact.
2) When you keep some heavy object (Sun) on that fabric, you bend this fabric and this causes gravity. Just as a marble starts revolving when thrown in to a bowl, planets revolve around the Sun.