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Let say we have 2 similar apples separated by a distance apart, just their mass energy alone is sufficient to cause bending in the space-time. I think it is this bending in the space-time that cause both the apples to accelerate but there shouldn't be any external forces to induce the acceleration, I've skimmed at the math it just says no bending no acceleration and that's not helping. I like to understand how bending in space-time cause the apple to accelerate?

[edit]okay I know the math shows that time is a vector(or scalar or even tensor*) too but that makes the matter even worst for me!

*just want to insured myself!


marked as duplicate by John Rennie general-relativity Dec 22 '15 at 12:41

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  • $\begingroup$ time is a scalar, acceleration a vector, curvature a tensor or a scalar ( trace of the tensor ) not completely describing the tensor. In articles, the curvature scalar is mainly used, with 1 = flat $\endgroup$ – user46925 Dec 22 '15 at 6:59
  • $\begingroup$ @igael Time is not a scalar. $\endgroup$ – Ryan Unger Dec 22 '15 at 7:00
  • $\begingroup$ @Ocelo7 : I was seeing time as a scalar , the unit vector coming with the frame $\endgroup$ – user46925 Dec 22 '15 at 7:12
  • $\begingroup$ I've linked what seems to me an exact duplicate. If you don't think it's a duplicate ping me and I'll withdraw my close vote. $\endgroup$ – John Rennie Dec 22 '15 at 12:42
  • $\begingroup$ @JohnRennie: so the math force us to think time is a vector and since both the Christoffel symbols and acceleration is not zero, so F=ma apply regardless of frame of ref. I still don't understand it at all I guess I'm back at square one btw thanks and hasta la, vista sir:) $\endgroup$ – user6760 Dec 22 '15 at 15:16