"I think we have to assume that "passing the horizon" is a subjective thing."
No, the horizon is an objective feature of the world. There's nothing subjective about it!
The horizon is the 3-dimensional surface in spacetime such that if you cross that surface, you can never go back out (to what's called "future infinity", and shown as a diagonal line here).]
Greg Egan (npub12cu…d38p) TobyBartels (npub1x4d…6lp6) Nick has moved to Mathstodon (npub1hnp…26ht)
