[Sarki]

On another note a theory which seems to fit particularly well is called Janus. The concept lies in the existence of a twin universe (ours being matter based the twin being antimatter based) merged together where the black holes are basically where the antimatter is concentrated and thus repulses all the matter hence this seemingly void. This is a succint summary but I hope it makes sense to the more knowledgeable readers of HN.

[Trombone12]

That makes no sense, black holes are like super much the opposite of a void. Further, repulsion is precisely the opposite of gravity.

[opportune]

Yeah you can interpret a Schwarzchild radius as a “void” in a certain sense (though more like a one-way dump) but a black hole is still very much a participant in the physics of our universe

[Sarki]

Actually, as far as I get it, black holes just don't exist: it's a journalist term coined for a mathematical concept. In short a black hole is how we call the possible existence of a place in the universe where there is no time nor energy, but it's no more than a mathematical possibility in the end as these are common variables in astrophysics.

[chriswarbo]

Black holes exist, in the sense that we have observed several phenomena that can be easily explained by the presence of a black hole, but which couldn't be explained otherwise. For example the orbits of stars around Sagittarius A* ( https://en.wikipedia.org/wiki/Sagittarius_A* ) and the X-ray emmission of Cygnus X-1 ( https://en.wikipedia.org/wiki/Cygnus_X-1 ).

> In short a black hole is how we call the possible existence of a place in the universe where there is no time nor energy

I don't know where you got this idea, but black holes don't have "no time" and they contain lots of energy (often several stars' worth).

Keep in mind that time is relative, so when talking about extreme situations like black holes it's important to keep track of what we're talking relative to. In particular, if an astronaut left a space ship, approached a black hole, passed beyond the event horizon and carried on going, that astronaut wouldn't really notice: if they looked forwards into the black hole they'd just see normal looking space, if they looked backwards they'd see their ship just as if they'd not entered the black hole. Relative to the astronaut, space and time appear completely normal; hence it doesn't make sense to talk about black holes having "no time".

Things would look different relative to the ship: the image of the astronaut they see would redshift as it approached the event horizon, and would also slow down until it came to a stop when at the horizon.

Note that this ignores tidal forces, which can be large around small black holes (the astronaut would certainly notice if their body were torn apart!). For large black holes like Sagittarius A* the tidal forces at the event horizon should be small enough to ignore.

[Sarki]

Thanks for the clarification, perhaps I was misleading, the point being that black holes have been deduced by mathematical interpretation, not observation of a phenomenon and today as per your own example we're still trying to find proof of their existence.

On the other hand, based on my understanding of the Janus model as I said in my first comment, the location of the seemingly void places are actually explained by the concentration of antimatter, which repulses matter through gravity. A possibly wrong summary of what I'm visibly struggling to communicate: This model explains how on the same way matter concentration attracts matter and rejects anti-matter, antimatter concentration attract antimatter and rejects matter.

[sorenn111]

The predominance of matter over antimatter I thought was explained by symmetry breaking at the ultra extreme conditions of early universe? Would there be a twin universe for other broken symmetries?

[teilo]

Symmetry breaking is an explanation, but we don't know if it's the right explanation. It's just the best we have at present.

[Sarki]

That's what is explained in the Janus model, both universes coexist in the same space and are rejecting each other through gravity, matter "won" over antimatter only by a tiny bit but sufficient to allow large portions of matter to remain. Though the appearance of both at the early times of the universe was in beyond colossal amounts, both being annihilated by each other when they met.

edit: typos

[chadcmulligan]

A genius by the name of Kanye was proposing this recently, though his work to, isn't widely accepted.