[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.