Black Hole Event Horizons

I don’t think it makes physical sense to talk about planets orbiting inside the event horizon. Black holes only shrink due to emitting Hawking radiation from the perspective of our frame of reference at a distance. We can consider the contents of the black hole to be undifferentiated mass/energy. From the perspective of a planet in that situation, that’s kind of meaningless as the process would take infinite subjective time.

Why is it that some experts say stuff falls into the center of a black hole while others say it slows down and never passes the event horizon? Is it just semantics?

I believe there is no interior of a black hole - because black holes never form. From the perspective of an object falling into a black hole, it hits an impenetrable wall of Hawking radiation and is forced out. From the perspective of a distant observer witnessing this, the object appears to "fall" pass the Schwarzschild radius because it's so red-shifted we simply can't see it. Then trillions of years later it's bounced out. Extreme time dilation causes extreme observat

If the universe is a black hole, would we be able to see anything falling into it after it crosses the event horizon?

Black holes don’t live forever. In principle, an external observer could watch you until the black hole evaporates. As mentioned above, if they never saw you fall in, then you never fell in. GR allows for disagreement on durations of events but not the events themselves.

Black holes have the property that things go from the event horizon to the singularity in a finite amount of proper time. Time reversed, an object shooting out from the singularity will hit the event horizon in a finite proper time. What would happen to us at that point?

Nothing strange happens when something falls into a black hole. We could right now be beyond the event horizon of a newly forming black hole. Unless a black hole is particularly small, in which case there will be notable tidal forces near the event horizon, the event horizon of a black hole is a pretty ordinary place hardly distinguishable from flat space. So nothing happens to matter or antimatter when it falls into a black hole.

I had a similar issue. This is my tl;dr understanding now.The thing to realize is that the view from outside shows the object falling in and getting dimmer and dimmer and more and more red shifted. You never actually see the object disappear.From the viewpoint sitting on the object, you fall right through the event horizon and get turned into mush, pretty quickly.So, black holes can be created as the matter can clearly fall past the event horizon and add to the black hole mass.

I'm not going to comment on the "cosmic censorship" hypothesis of black holes since that's actually an incredibly difficult topic, but regarding the tidal forces that would rip you apart, there are certainly large enough black holes that would allow you to comfortably enter the event horizon without being ripped apart. But just to give you a taste of how counter-intuitive this subject can be, consider that despite the fact that light cannot escape a black hole it is conjectur

The weird thing is that it differs from your perspective. If you're looking in from "infinity" (ie. where the gravity field of the black hole is negligeable) there appears to be a region where nothing can get to : the event horizon.After all, what does one see when looking at a light source falling into a black hole. That light source slows down as it approaches the event horizon. When it gets close you'll see it dim. That's because time is going slower for that light