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I didn’t understand whether the author is implying that this happens to all black holes or whether the model only applies in some circumstances. I definitely didn’t understand whether this is suggesting that expanding universes can be contained within black holes that look like fixed-size finite objects from the outside. And what happens to the inner universe when the parent black hole evaporates through Hawking radi…
Not many people these days like to hear this (I myself was one of them), but the answer to this is in Genesis. There's a reason some of the most famous mathematicians, scientists, engineers, and philosophers of all time believe(d) in God. The Hebrew name of God, YHWH, literally means "He Who Is." In other words, the Self-Existent One. The father and originator of all things that were, are, and will be, who exists out…
Who Created God? No one? Why does the universe need a creator if God does not?
Where does free will and evil come from if God is "originator of all things that were, are, and will be". For true free will to exist it must have a source of entropy which denotes something outside of Gods control and design otherwise everything is deterministic as set forth by God.
> The black hole universe also offers a new perspective on our place in the cosmos. In this framework, our entire observable universe lies inside the interior of a black hole formed in some larger “parent” universe. Does it also follow that black holes in our universe contain universes internally, beyond their event horizons?! Seems like it should. Mind-blowing.
It's not a new idea, although I don't think it would be accurate to describe the other universes as "contained" within the black hole. https://en.wikipedia.org/wiki/White_hole#Big_Bang/Supermassi...
It’s holes all the way down
I've often wondered about this. I don't have any direct physics training, but it's something that felt really plausible after I learned that the mass of a black hole is linearly proportional to its swarzschild radius.
As the size of the black hole goes up, its overall density must decrease. Combined with the other observation that our universe has uniform density at large scales, it seemed really obvious to me that there existed some threshold at which the decreasing density of a very large black hole, and the fixed density of our observed universe.. would cross.
I used to muse about this question with some other tech colleagues that liked talking about physics stuff but never really got a clear answer to this.
On a side note - I'm absolutely fascinated by the implications relating to this. I'll post a follow-up thought I'm hoping somebody else has also thought about:
I've seen discussion of dark energy mostly presented as a surrogate for real energy. That there is some underlying energy "accelerating things away from each other".
I always felt uncomfortable with that characterization. It seems more reasonable to me to think of dark energy as _negative energy_ - i.e. a loss of overall energy.
In a classical system, two things moving away from each other stores potential energy that can be recouped at some later time. Dark energy doesn't work this way - things accelerate away from each other the further apart they are. From a global perspective, it's an energy loss.
The energy loss pervades to the quantum world as well - photons that start off high frequency arrive low-frequency.
It somehow feels more appropriate to me to think of dark energy as energy being extracted out of the universe, in some form never to return. Maybe like a black hole evaporating as observed from the inside?
When I asked this of some people in real life, I was pointed to answers that indicated that the "energy" component in dark energy is normalized into the "tension" of space somehow. As I mentioned before I'm not really studied in physics, but that explanation felt unsatisfactory to me.
> The Big Bang is often described as the explosive birth of the universe – a singular moment when space, time and matter sprang into existence. It is indeed "often described" in the media as such. However, that is _not_ the currently accepted theory. "What if there were no space and time before the Big Bang" is just Stephen Hawking's pet theory.
Not many people these days like to hear this (I myself was one of them), but the answer to this is in Genesis. There's a reason some of the most famous mathematicians, scientists, engineers, and philosophers of all time believe(d) in God. The Hebrew name of God, YHWH, literally means "He Who Is." In other words, the Self-Existent One. The father and originator of all things that were, are, and will be, who exists out…
There are countless other religions that believe in a deity who created the universe. These deities either created themselves, or had always existed outside of space and time. To that end, any one of those deities would be on equal footing with YHWH. I don't think that it is appropriate to axiomatically claim that a certain deity exists because only that deity could have caused the universe to exist.
Earlier quoted context omitted.
Not true. The arrow of entropy has a direction and it's the same as the arrow of time. There's not a good explanation for why though.
There's no arrow of entropy, it's an invented useful model to describe something that nature does. Everything is like that, I.e. there's no electric field, it's a useful way to do calculations about particle interactions.
https://journals.aps.org/prd/abstract/10.1103/PhysRevD.111.1...