Even worse, we don’t know what black holes really are.
Is there a discontinuity in spacetime? Is the discontinuity point-like or spherical, or even toroidal? Do physics even exists within? Is “within a black hole” even a reasonable concept? We don’t know! We’re still arguing about wether black holes can delete information from existence.
My favourite black hole fact, coming from the character of the space-time tensor and how it changes, is that as you approach a black hole, time goes sideways.
I don’t think my lecturer put it quite that way, but he showed that as you get close, the time dimension comes to look like a space dimension in the tensor, and the space dimension that points into the black hole, looks like a time dimension!
Even worse, we don’t know what black holes really are.
Is there a discontinuity in spacetime? Is the discontinuity point-like or spherical, or even toroidal? Do physics even exists within? Is “within a black hole” even a reasonable concept? We don’t know! We’re still arguing about wether black holes can delete information from existence.
My favourite black hole fact, coming from the character of the space-time tensor and how it changes, is that as you approach a black hole, time goes sideways.
I don’t think my lecturer put it quite that way, but he showed that as you get close, the time dimension comes to look like a space dimension in the tensor, and the space dimension that points into the black hole, looks like a time dimension!
Yeah, time-like paths are mind bending.
I’ve always though about that as the interior of the black hole has been left behind in the time direction, like a sausage casing.