Say we're in a universe with a +- metric signature. We're looking at tx, ignoring yz. Rotating within a 45 degree cone (which hides the hyperbolic geometry of

Say we're in a universe with a +- metric signature. We're looking at tx, ignoring yz. Rotating within a 45 degree cone (which hides the hyperbolic geometry of +- space) is easy. That's just normal acceleration. Rotating more than 45 degrees is the hard part. That corresponds to going FTL. It's hard because of the hyperbolic structure of +-. Once you're going FTL, changing your direction to point backwards in time is trivial; you just turn your engines on and accelerate. Read Greg Egan's "Clockwork Rocket" and "Dichronauts" books and support material on his website to develop an intuitive understanding of spacetimes with ++++ and ++-- signatures and (by contrast) our own spacetime with a +--- signature.