Understanding Space-time curvature

According to general relativity mass curves space-time but not just space. It means an object moving in space will go in a straight path for any amount of time but once it approaches any other object it starts to deviate from straight line path and moves in a curved path.

Let us consider a mass A, comparable to the size of mass earth, initially moving alone in space with velocity V from point X in space. Because there is no other mass in its proximity it will follow a straight line path. Let us assume at some point, Y it approaches another mass B, comparable to mass of sun. Once the mass A is in vicinity of mass B, it will no longer follow a straight line but it follow a curved path in space as it approaches mass B.  We can predict three paths for mass A

1.     Mass A spiral around mass B and collide with mass B

2.     Mass A revolve around mass B

3.     Mass A follow a path of curve and fly away(Gravitational lensing)

Depending on the mass of A and B and its velocity it may takes any of the above three paths. But we assumed comparable sizes of earth and sun for mass A and B respectively. So, it will probably take a path of revolving around sun if its velocity is same as that of the earth.

  

The degree of curvature of mass A path depends on strength of gravity between mass A and B but path of mass A is not curved because space is curved. 

Curved Space                                                                             Curved spacetime