> F) ... why we can't just assume that there isn't spacetime inside black holes Spacetime isn't a substance. I guess what you are asking is, can our universe

> F) ... why we can't just assume that there isn't spacetime inside black holes Spacetime isn't a substance. I guess what you are asking is, can our universe be non-simply-connected 3+1-dimensional manifold (see 2-dimensional version at first diagram @ <https://en.wikipedia.org/wiki/Simply_connected_space https://en.wikipedia.org/wiki/Simply_connected_space>, imagining the additional 1+1 dimensions is an exercise for you) with what we think of as black hole horizons being a region very very very close to a "hole" in the manifold. The answer is probably not, and depends on the Topological Censorship Hypothesis <https://en.wikipedia.org/wiki/Topological_censorship https://en.wikipedia.org/wiki/Topological_censorship> being correct. If the universe works the way we think it does pretty much everywhere far enough away from black holes, then a hole-like defect can't last for the billions or trillions of years that an astrophysical black hole will (we have good evidence that some galaxy-centre black holes have been around at least hundreds of millions of years, and it is safe to assume we'll be able to expand that out to billions). Hole defects also can't grow like black holes do by ingesting partner ordinary gaseous stars, or by colliding with one another and merging, or rather the electromagnetic signals would be radically different. This makes a couple of assumptions about the massless wave function for light. Things get tricky if we introduce an invariant mass to light (i.e., electromagnetic radiation has a sub-infinite range it can travel) or otherwise break the equality of c and the speed of light in free space. Maybe one can contrive a longer lifetime for regions that break simple-connectedness. However, you still have to pile things up around the hole, and there's no reason to expect gravitation of the pile of things will help you there. Squeezing matter up against the "edge" of a topological hole will also brighten the matter, and you really want it to dim and fade away for observers around here, since that's what we see from astronomy in the aftermath of tidal disruption events, binary merger ringdowns, and infalls of gas clouds. In standard theory black holes get this dimming by directing some near-horizon radiant energy inwards. If there's no inwards, how do you make the heat glow become invisible? As well as the dimming, visible spectral lines shift into the infrared, and the apparent angles and areas of an infalling object should change. > In other words, that whatever determinations make up the universe are undetermined in those places? I can't guess what you mean by that.