What is a black hole?
The word black hole is sometimes used in popular communications and speech to referred to different things. To event horizons and to singularities. When referring to singularity it usually refers to a singularity that can be reached in the future to contrast it with a white hole whose singularity can be in your past. However a timelike singularity could be either (for different observers) or both (for someone that hits it). When referring to an event horizon it is a one way surface for a family of observers the observes that don't cross it never see the inside as part of their causal past. To me, this is more intuitive as the black part of the black hole it describes that you don't see it.
The general explanation is that a black hole is small region in space with such strong gravitational effects that nothing can escape and even light is trapped inside of the event horizon.
This is a bad explanation. Firstly it makes it seem like it is a region, it seems to not make no distinction between spacelike singularities and timelike singularities and in general seems to not reflect that we are talking about events in spacetime and the when is as important as the where and that the two don't really have meaning apart from each other.
Black holes as portals to other universes are not a new idea, but it often is discarded as it is difficult to explain how such portals can be stable.
Lack of stability is not something to take lightly. It means you can make a mathematical model that has a wormhole from here to there and have two totally different universes connected to each other and your friend can make a totally different mathematical model that for instance doesn't have a wormhole from here to there and have two totally different universes. And the two might "initially" disagree only in very tiny ways.
Its pretty much like if someone says they could balance a perfectly sharp pencil on a perfectly flat table forever by just placing it perfectly vertical and point down and then walking away. Sure, maybe there is a mathematical model that says that it stays there forever but any initial conditions that are even slightly different have a drastically different outcome.
Hawking describes black holes as one way portals, and if you travel through you can’t come back. This makes sense and don't violate the event horizon
For a rotating black black hole was always around there can be two horizons
When you are in between then you can affect the singularity but it can't affect you. You are not forced to the singularity but instead are forced to the second horizon which is farther inside.
When you finally get to the second inner horizon you are now in a region of spacetime that can be affected by the singularity.
And here we have no idea what that should mean. Maybe it doesn't matter because inside the second horizon you are no longer forced you could maybe avoid it and since it could be on your past it already affected the things around it and SL you only get the second hand effects. But we don't know what the second hand effects are since we don't know how the singularity affected things.
And that is partly because in this simplest of models the singularity was always around. The event horizons were always around and no matter how long ago you entered by the time you go past both the outer and inner horizons then the singularity was already around and had always been around.
It is like there are two distant pasts that both affect the singularity on past the last you saw before you crossed the event horizon the past of things and light that crossed before you. And a different past from the other side the side that was already in the past of everything that ever came from the outside. But worse there might be time travel in that other past so is it really the past? But that is worse. But all these issues of whether you can affect it versus whether it can affect you are essential.
And this is not something to count on this basically assumes that there was this weird universe and then if there was then there is. A bit self causing so you can't know if it will happen when you cross. And then when you find out it is unstable and that after you cross the inner horizon you could be affected by a singularity in your past, last in the sense that it already had time to affect earlier events in unknown ways so you don't know how those events will affect you now that you are in range. Plus if you look away from the singularity in this region you will instead be affected by regions (unstable regions) with time travel. And they can affect you. And eternal region that has always existed and had time travel between any points. That can affect you. Its pretty Mich just as bad as the singularity for not knowing what will or could or must happen to you.
After you cross that inner horizon you can turn around and head up. But you always go the future (I'm assuming to want to avoid the region that has time travel) and so whe you get up to the region between the horizons it is later.
How later? By the time you turn around and get to the inner horizon on your way back up you will have seen every one that will ever cross the horizon and you will see them also cross the inner horizon and you will see them see the singularity. So this is latter. The region of spacetime where people fall in the outer horizon and are forced to fall from there to the inner horizon is now over and. You have seen it all with your own eyeballs by the time you get back to the inner horizon.
So when you cross the inner horizon for the second time this region of spacetime is totally different it is a region where everything goes up instead of everything going down. It is a different time. And being at a different time is important. That region between the horizons where everything had to go down, it is over and done and in the past. This is a new thing. This is a region that has been affected by a singularities and can see a region behind farther down that is as old as your own universe but that has always had time travel.
And since before you reached the inner horizon you could have gone to that region and then used time travel and then come back out some of those things you see in that time travel region could be your future self who could beat you to the inner horizon before you get there thus you might have to turn to go to the time travel region to avoid making a paradox. It's a bad bad region beyond both horizons.
But on your second time between the two horizons this time everything is heading up and there is no turning back. And to emphasize the fact that everything is heading up means this is a different region of spacetime. The when and the where matter. Both equally as much.
In this region you are forced to go away from the inner horizon and towards the outer horizon. And eventually when you cross it you are no longer directly affected by the time travel region or the singularity. However you are now is a region that looks like the region outside a different black hole.
But is it a different universe? The mathematical model has it look exactly like yours, really totally like yours. What's the basis to say they are different?
But how does the black hole portal look like where it enters that other universe?
I just described the journey from one universe to a different universe. You had two horizons and two regions between them one where everything must go down and one that is later and everything must go up and in the things go up region of spacetime (so the time part matters, in fact this region has every part being later than every part of the going down region) you have already had to deal with seeing singularities and time travelers. And had to deal with potentially seeing things that were your own future self. And this things can still directly affect you on your journey upwards.
It is in no way as simple as just having a region that takes you from a a here to a there. You have time. You got to see everything that ever crossed from your universe you got to see them all cross the inner horizon you got to see them all deal with a region where they had to risk seeing their future self. And so before you got to the other universe you were very much after your old universe. If someone promised to go in after you you know if they did. You don't have to wait to find out if they did.
This is meaningful when it comes to information. And all of this happens before you reach the other universe.
Well energy and information has to come out of the portal, and this portal seems to be quite the opposite of a black hole, it seems to be a white hole.
You saw the information before you got to the other universe. A white hole like from your link is an event horizon that you can only cross outwards in the future direction. So it is both the horizons on the way up. Both of them. And by the time you crossed the inner on on the way up you have all the information about what crossed in the black hole ever, things before you and things afterwards. But they are getting all mixed up with the time travel region.
But the time you get by to the outer horizon on your way up then all that information had a chance to go back in time and get all mixed up with an entire universe that had its own unknown history, has time travel, always had time travel and is unstable to boot. Your information is mixed up with that.
So maybe our black hole is an opening to a one-way wormhole that leads to a white hole in the middle of another galaxy in another universe?
This fixation on where you come out (like your picture of the two holes) ignores completely the essential issue of when you come out. When you come out there is again a whole new universe with its own past, things that you maybe affected when you crossed that inner horizon on the way up (that's the last time you affected the singularity). So there is a whole new world and you need to come out to a when as well as a where.
So you can imagine this new universe has two regions of smaller than event horizon. An older white hole event horizon (where and when) you come out and a newer black hole event horizon. The older one only has things come up and the newer one only has things only go into. And the newer one has every event in it be after every event in the older one.
So when you come out you are in the psst of every single thing going in. That means everything else gets its chance to come out before you could go in. So it is in no way as simple as thinking it is a where. And thinking the white hole and the black hole are in different places, they are at different times.
.But we have only indirectly observed black holes in our universe, and we might then wonder if our universe is currently being sucked into another universe through black holes?
Sure, we might already be inside a black hole event horizon and just don't know it yet. But not like any I just described, those were eternal ones. For instance they always had the white hole event horizon spewing thing out up until it turned into a black hole event horizon. Which keep in mind is a path to different regions of spacetime. The white hole event horizon is a surface where things comes from the last and increase their radius and the black hole event horizon is a surface where things go to the future and decrease their radius.
These universes are eternal and so were the holes.TTheuniverse was always infinitely big and the hole was always the same size.
But maybe we have white holes in our universe, where energy, information, and possilby matter and antimatter enters our universe. But where are they?
When are they? My whole answer is that you can't ask where without asking when. For the example I gave you they are the same wheres, just at different whens.
When you have an eternal universe it is possible to have every finite time say that the white hole happened in the past.
The black hole has the white hole in its past so if you have eternal black hole then the white hole was already over and for every finite time. So you can imagine that a second after you come out the black hole you look around and notice everyone that wasn't coming out with you has their own watches and you can start keeping time with them their coordinate system might be based on radar time.
Radar time is when you look at your watch and send a radar pulse to an event and then wait for it to deflect back and when it gets back you look at you watch again. If you subtract the times and divide by two and then multiply by the speed of light you get a radar distance. If you average the time you get a radar time (time you saw the event corrected for the radar distance and the light travel time).
If people in that new universe use radar time to assign times to the events when you came out they asssogn $t=-\infty$ to the event you came out. Which actually makes sense. No matter how far back they went in time they never had a chance to influence you. You came from a different universe. When you stay outside the holes and use radar time you assign $t=\infty$ to the black hole event horizon because those events never affect you.
So the black hole event horizon are events that can never affect the outside universe and if you are still on one side you can escape.
And the white hole event horizon are events that can never be affected by the outside universe and if you are now on one side you can't go back.
White hole horizon. Can't affect it, can't get to it: $t=-\infty$ makes sense.
Black hole horizon. Can't be affected by it, can always avoid it and instead live as long as you want: $t=-\infty$ makes sense.
But what if quasars are a white holes where energy pours out from a wormhole?
Your question isn't even well posed unless you make a 4d theory that has times as well as locations. And radar time is a perfectly physical way to assign time to some 4d regions of distant events that are outside horizons and it will naturally assign $t=\infty$ to black hole event horizons and will assign $t=-\infty$ to white hole event horizons. And it can nicely have each time be determined by the previous time, because it is made to do that and it has a fine operational definition for anything that stays out horizons.
We see from the high orbital speed of the nearby stars that Sagittarius A* has a mass of 4 million solar masses and such a huge mass in such a small space has to be a black hole.
Whether there is one depends on your time. You can use radar time and the horizon hasn't formed yet. And how do we know there isn't some new kind of interaction that happens on very short time scales that normally averages out over large time scales but with the time dilation can allow the matter bounce back?
People make assumptions about physics we haven't seen when they say it forms. And their assumptions, if correct, mean we will never see this physics. And different physics says it doesn't form. And even if it did form we can choose a coordinate system (with radar time) that explains all observations made by outside observers and that assignes the black hole event horizon to be just one part of the $t=\infty$ surface.
But this method of logic deduction also have another solution, as there is also another object that also explains the huge gravity and radiation of Sagittarius A*, a white hole would explain it perfectly.
Wrong. Things can't go into a white hole the inside is the past. Things might be able to go into a black hole because the inside is the future. Look up a Penrose diagram. Learn to read it. Going more up than left.right is how you move forwards in time. A constant time surface or constant r surface could point any direction could be "(" or " )" or a smilely or a frown or a line. But going more up than left/right is an allowed motion if they drew it nice. And a finite curve might actual have room for an infinite number of meter sticks or clock ticks its just to allow you to see a lot and reason about it.
So if things are going in then it isn't a white hole. Now maybe there used to be. So maybe you see things that left but haven't gotten very far yet. That might be what you mean I just can never tell when your whens are.
"Like black holes, white holes have properties like mass, charge, and angular momentum. They attract matter like any other mass, but objects falling towards a white hole would never actually reach the white hole's event horizon." source
I disagree that they can fall towards it. Radar coordinates are reasonable coordinates for external regions of spacetime and I don't see how a future pointing curves goes "towards" a $t=-\infty$ surface. It could go towards where it was but that is different time is important. Otherwise a black hole and a white hole with horizons at the same place look the same when one is clearly in the past and the other is in the future.
If Sagittarius A* is a white hole at the end of a wormhole,
You said is and white hole which can't be right unless you are coning out of it and hence came from the other universe. Popular communications caters to people wanting to have simple conversations about distant events.
Don't be fooled. If you want I understand it, draw the spacetime diagram. You can't understand something in relativity unless you can draw the spacetime diagram."
than the black hole at the other end of the wormhole.
There are many different kinds of wormholes. If you have spacelike singularities and a white hole in the past and a black hole in the future than nothing gets from one universe to the other. Everything has the white hole in its past. Everything has the black hole in its future. Until you get to the actual $t=\infty$ surface which only has the black hole as part of it. And the $t=-\infty$ also only has the white hole as part of it.
If you have timelike singularities then the wormhole is traversable. Information can get from the outside to the inside and all the information that ever falls in can mix together and mix with a whole universe on more information and then be stored up time travel and then be skewed out into a different universe so long in its past that it is basically a portion of that universes $t=-\infty$ surface.
And yes other options might be possible. But you will have to say when things happen. And it could be at least this complex.
We would expect the white hole to have flashes or energy bursts during periods when matter, antimatter and energy falls into the black hole and comes out of the white hole,
When? Each universe has white holes in their past and black holes in the future. So what is this magic when you refer to?
If Sagittarius A* is a black hole on the end of a wormhole, like Hawking suggests, we would not expect it to have a big radiating accretion disk, as it is not a singularity, but the opening to a one way tunnel through time and space, and matter will probably be pulled into the wormhole before it lights up enough to be easily observed.
This is so wrong in so many ways. There are singularity theorems so if you extend the metric according to Einstein's Field Equation then it the metric blows up after a finite proper length or time. The singularity might be timelike and hence avoidable. It might spacelike and unavoidable or Einstein's Field Equation could fail and hence GR breaks and then we don't know what would happen.
The event horizon and the singularity are different things. It is even possible to have either one without the other.
So if Sagittarius A* is a wormhole it seems to be more likely that it is the white hole at the end of that wormhole.
Spacelike? Timelike? When? You haven't stated enough information to be clearly identifying an option let alone a likely one. Radar time for external observers will always put white hole event horizons before black hole event horizons. Chronologically before.
The wormhole would not collapse as the binary white hole and black hole has oppositely directed wormholes that spin, twin and stabilize each other.
This sounds completely made up, there many non traversable wormholes that have a white hole and a black hole. And if you have angular momentum then the same singularity can have black hole horizons and white hole horizons. But then they are like I described the white hole horizons in the future of the black hole horizons
Rather than black hole singularities, wormholes are much neater concept which don't break down the laws of physics, but rather expands the laws of physics.
It is fairly easy to make time machines out of many wormholes that connect to the same universe. Some wormhole have singularities. Some wormholes are not traversable. And you are just being too vague so I talked about the first most basic issue you seem to miss which is that time matters.
Our universe would neither be feeding some other universe, but would be stable and balanced together with that other universe.
I think you fail to see the basic fact that white hole event horizons are in the past and black hole event horizons are in the future (to external observers outside the horizons and that never cross them). The one way definitely has feeding but in a specific temporal order.
And Hawking would be able to take his space ship travel through the galactic black hole, come out from a white hole in another universe, observe the galaxy there, find the black hole there, jump through it and come out of Sagittarius A*, and return to Earth.
If he did that then he can arrive before he left and show up and that party he threw for time travellers. Since he didn't show (no time travelers showed up). Then he is unlikely to feel safe about your promises. He would have arrived out of any white hole event horizon before going in any black hole event horizon because the radar time of the former is $t=-\infty$ and the radar time of the latter is $t=\infty$ and radar time puts later times later.
But such a model may be in conflict with the big bang, as the past can be created by the future through wormholes, and we have to allow multidimensionality, parallel realities, and circular time. All which is very interesting, but we have to take that discussion another time.
You were bringing it up all the time.
The black hole and the white hole can neither merge as they are one way portals which are oppositely directed,
Yes, you and your great-great-great-great-great-great-grandfather can never merge because he was gone long before you were around.
it seems there is a multidimensional push between them which keeps them apart.
No, you and your great-great-great-great-great-great-grandfather don't feel multidimensional push he was gone long before you were around. So there wasn't a two of you to feel a push.
But the binary black hole and the white hole also want to connect by forming a new worm hole between them and short-circuit the system, but there is no fabric of space left, but they might create multidimensional pull towards each other. The white hole and the black hole ends up in a push pull relation keeping their binary distance.
There is consensus, that if wormholes exists they have great energy and force, but a push and pull force that surpass time and space?
Push and pull are the wrong ideas. Things evolves. Pasts combine to make an event. Which can be part of the past for new events. (Or old ones when there is time travel.)
Yes, gravity says how space and time together evolve and so how a white hole plus outside can become a black hole plus outside. And gravity doesn't overcome space and time it evolves it.
Galaxies don't spin like a solid disk. And different galaxies spin differently so have different amounts of dark matter so this is hard to explain with a new force.
The forces might act instantly,
There is no common shared time, so the word instantly doesn't even make sense.
And we have no way to observe this force, it is similar to how the neutrino disappear and reappear, but this force is always out of view as it is not in our linear time.
If you go into a black hole and it's a wormhole to another universe you will enter that universe in the past
Even if it is a wormhole the wormhole might not be traversable in which case you get end up hitting the singularity rather than getting to another universe.
enter a black hole in that new universe you might get back, but travel even further into the past.
When you say even further it makes me worry you misunderstand. There is not some global universal clock.
By jumping through several such black holes you will come to the beginning of time, assuming time is linear and there is a beginning,
I never assumed time is linear, you might have had to deal with time travel before you got put. And the very first white hole you exit might have you enter so far back that you everything in that universe thinks you are older than them.
And there are two senses of old. If someone couldn't stop you from doing something because light couldn't reach you in time then you are far away but also have been around for a while. If you hadn't been around they could have sent a message earlier telling you not to do it. Then there is how long your own clock has ticked. These are different I'm general (relativity). You can have your clock tick just a little but people think you've been around forever. That is what happens when you come out of a white hole. Everyone outside thinks the event of you coming out was unreachable by them because no matter how early in time (or where outside the event horizon) they sent you a message it never arrived in time you only got it after crossing.
So when you exit is before everything in that external universe. There isn't a further. And I see no reason to insist it be a different universe if later you are going to allow one of these universe you get to by these wormholes to be the original universe.
And this can happen even if there is no beginning.
there it will be no black wormholes as there is no past.
Not following you.