Replying to
@futurebird @gregeganSF And if something were traveling in spacetime along a timelike geodesic, it would be going faster than the speed of light.
And perhaps traveling backwards in time, from a relativity point of view. The symmetry transformations of the space don't necessarily preserve forward vs backward in time, for timeline geodesics. That's another way of saying that two different observers looking at the two endpoints of a timelike geodesic might disagree about which end "happened first."