If we think about the time-reversed trayectories of a test particle whose trayectory is curved by the presence of a mass, the time reverse of that interaction looks also attractive and gravitational.
That is one of the main arguments in order to explain that general relativity and gravity are invariant under a time reversal.
But I believe that the addresing of this problem is initially wrong, because we cannot talk about a time reversal been exactly the repetition of the past, if CP symmetry is violated an thus, T symmetry is also violated. That violation means that physics under a time reversal should not follow exactly what happend in the past, and that statement is taken as an arbitrary assumption in the example explained before.
At a macroscopic level, Yes, certainly. At a quantum level, we don't know yet ...
The CPT theorem assumes global Lorentz invariance, whereas gravity has only local Lorentz invariance. That's why it's wrong to appeal to the CPT theorem, when discussing gravitational effects.
In general relativity, however, there are future singularities-those of black holes-and past singularities-those of, so-called, white holes. And they can be related by time reversal.
- Badges
- Science topic
- Similar topics
- Elementary Particle Physics
- Particle