The article below was written in 2002. I don't know what got me to thinking about the similarity between black holes and the big bang. It was probably a book, an article, or a TV documentary on cosmology. I may have heard (without specifically remembering) about Lee Smolin's theories about the origins of universes (that's right: universes, plural), and so my imagination ran with the idea. I wasn't the first to imagine that there was a connection. But the idea grabbed my imagination, and I ran with it. Thus this article, as unscientific and uninformed as it may be. More on this in the Forward (at the end of the article). - Tom
To state the theory in the shortest possible terms: Universes exist within black holes. When a black hole is created, it spawns a new universe in another dimension. Which means that our "big bang" occurred when a black hole came into being in another universe. And which means that the black hole at the center of our Milky Way galaxy (and at the center of every galaxy) is, in essence, an entire other universe in and of itself.
TO EXPAND ON THAT A BIT
Perhaps first I should say that I am not an astrophysicist. I have not studied the math, I don't understand String Theory in the least, and I do not have a degree that relates in the slightest to the sort of science that I am sullying by writing this. I am, truth be known, a brazen pretender. At Boy Scout camp and during reenactment outings during the Civil War Centennial, I stargazed and pondered the heavens. During college I operated the campus planetarium (thereby acing my Earth Sciences 101 class). I have read (and mostly understood) some of the books of Stephen Hawking and Carl Sagan (and, more recently, Brian Greene*). I read a lot of science fiction in the 1960s (back when it was good; when it was about science more than about magic). So what I say herein should be taken as nothing more than the musings (the thought experiments) of a rank layman.
What happens when a black hole comes into being?
Matter (a tremendous amount of it, usually all the matter of a giant star) is condensed into a mass so intense that it collapses into what the scientists call a singularity. A pinprick in the fabric of space and time, at the bottom of an unimaginably strong gravity well. Even light cannot escape from a black hole, the gravity is so intense. There are a lot of sources for information about black holes - I recommend http://www.google.com as the best search engine on the web (and of course, there is also the local library).
But we do not, and can not, know anything about what goes on inside the singularity.
In addition, we do not, and can not, know anything about what happened before the creation of our universe. If time existed before then.
It often happens that when we have two unanswered questions, all we really needed to know was that the two questions were about the same thing, and bingo - the answer can then be found.
TWO MYSTERIES - ONE ANSWER
For example, when I first moved to California, I learned about the area over time as I lived here. And as I became familiar with the outlying areas, I came to have two questions (among many others). One question was about this place I heard of, in conversations and on the radio: "La Hoya." I wondered where it was, exactly. Occasionally I would look on my Auto Club map, and was unsuccessful in locating this elusive place. But as I looked on the map, I saw that there was a sizeable area known as "La Jolla." Yet I never heard about anything happening there. It is a large area, and it would be logical that news ought to happen there once in a while - or that I would meet someone who had been there. Yet such was not the case.
It seemed to be two mysteries. Until one day I realized that in Spanish, the "j" is often pronounced as "h" and a double "l" is pronounced as "y" - which meant that "La Jolla" is pronounced "La Hoya."
It seems stupid, but the connection between the two mysteries had been unknown prior to this realization. It hadn't been two mysteries - it had been nothing more than one unknown.
So it is with the questions of "what goes on inside a black hole" and "where do universes come from." It isn't two questions, two mysteries. The two questions are connected, which means there's actually just the one. At least, that's my theory.
THE BIG BANG
We know that our universe began with a big bang. But it is often assumed that we should not question (because we can not know) what happened "before" that. The reason I put quotes on the word "before" is that time itself (insofar as it can be defined in terms of our universe, which are the only terms we can use) began with the big bang.
To postulate a time before the big bang means to postulate a place outside of our universe.
Okay, so what? We can think, can't we?
When black holes were first postulated, the very notion was all but discounted. Proof of the existence of black holes was sought, and some texts (even on the web, today in 2002 as I write this) still mention them as though they are speculative phenomena. Let us proceed based on the notion that they do indeed exist, and that they are actually fairly common (there being at least one supermassive black hole at the heart of every galaxy). I am not equipped to provide the reader with convincing evidence for this, but we have to start somewhere.
Imagine what happens when a black hole comes into being. A gigantic star collapses of its own weight into itself. All the matter and energy that suddenly disappears from normal space-time has to go somewhere. But where?
Have you ever squeezed a partially-filled balloon, filled with either water or air? The gas or liquid in the balloon has to go somewhere, and our hands invariably leave an opening somewhere - part of the balloon bubbles out between this finger and that finger, making an extrusion.
Same with a black hole. But the extrusion does not (and cannot) take place in our normal space-time. In our "dimension." In our universe.
The extrusion cannot occur in our universe, so it must occur in another one.
Commensurate with the disappearance into a black hole of huge amounts of matter and energy from our universe, a big bang occurs in a new universe, one that comes instantly into being in another dimension.
BIRTH OF A UNIVERSE
As the new universe is born, its own physics, its own time scale come into being. Just as a balloon extrusion pops into being through a gap between our fingers, so a universe finds itself expanding into its new dimension. But the simile (comparing a universe and a balloon) doesn't hold water for very long.
As a big bang occurs, the matter is not bound by any rubberized "skin." The dimension into which the new universe is born is free and unbounded, because it is a new one, created just for this case. The matter and energy that fell into the black hole was under an unnatural compression, but here in the new universe it is free to expand. In fact, as the new universe comes into being, there is in effect a universal vacuum that demands expansion. A universe spawned into an empty dimension has nothing to stop it from expanding.
As the matter and energy enter the new universe, the elements of matter and forms of energy of the old universe are forgotten. Elements that fall into a black hole are destroyed - the very atoms are crushed into their elementary parts. Matter that emerges into the new universe within a big bang is (for lack of a better word) elemental. It has yet to be formed into material that is consistent with the laws of this new universe.
Some readers may be concerned that the matter that goes into a black hole is not enough to make an entire universe. This theory holds that it's a matter of scale. The material that emerges from a big bang is enough to fill a universe.
Some readers may be concerned that the life of a black hole is not lengthy enough - surely a universe lasts longer than does a black hole. This theory holds that (again) it's a matter of scale. Time as it exists within a black hole stretches almost infinitely, compared with time outside a black hole (in the universe in which the black hole exists).
Some readers may be concerned that black holes continue to suck in matter, which would mean that in the other dimension (the one where the black hole's internal universe resides) the big bang is not a one-shot event; new matter would be constantly getting added. If this is the case, then why does our universe not have a fountain of new matter? To which I say, how do we know that it does not. Perhaps it does.
A BIG CRUNCH?
Black holes are not forever. They do leak some energy (that's one of the ways that we "see" them), and they can eventually dissipate.
If my wacky theory is correct, then what does the undoing of a black hole portend for the universe inside it?
It probably indicates that universes do end, not with a bang but with a whisper. Perhaps the universe shrinks in size as its matter is dissipated into the parent universe, or perhaps it simply fades out without shrinkage.
Or perhaps the death of a black hole doesn't mean just the end of a universe contained therein - a universe inside a black hole is most certainly itself sprouting numerous other universes (by means of black holes inside those universes). So a black hole is always expending itself by creating its offspring, who go on and spawn yet more universes. Matryoshka! But, as with people, when the parent dies, the offspring continues to survive. This being only natural.
It's also conceivable that continuing expansion constitutes a shrinkage, if looked at in a certain way. The theory needs further thought experiments along these lines. But one factor hampering things is that although we have one example of a universe's beginning to work from, we do not have any examples of a universe's ending from which to postulate.
The only way to get from one universe to another is through the singularity of a black hole. The trip is not survivable (not even an atom, as mentioned above, nor a beam of light can survive the journey). Forget about travel between universes; it's impossible. We exist only in our own universe; we can neither exit it "up" to the "mother universe" (and where would we do so, in any case - where is the door? There is none) nor "down" through a singularity into an "offspring universe."
I think dark matter is space-time itself. Space-time itself actually has substance and mass, and this should be more evident in the vicinity of massive objects like stars, black holes, galaxies, etc.
So there you have my wacky theory of Black Holes, Big Bangs, Universes, & Everything. Our universe began with the creation of a black hole in another universe. Which means that there would be countless other universes, many of which are probably very similar to ours (it being only natural for them to be so). And with the countless black holes of our universe, countless more universes exist. Like the Russian nested dolls called matryoshka, universes are realities within other realities.
Update, June 2012: This InsideScience article backs up the wacky theory, and even explains why it works: the secret is torsion.
* In reading Brian Greene's The Elegant Universe in 2004, I found that the notion that black holes contain universes was a theory put forth by Lee Smolin, a theoretical physicist, professor of physics and member of the Center for Gravitational Physics and Geometry at Pennsylvania State University. That notion is Smolin's, but the words used above are my own - I've expounded on my wacky imaginings based on the notion that big bangs and the origins of black holes are one and the same thing. Having now started to look into Smolin's writings, I find that some of my imaginings may be a little off, but aren't necessarily all that wacky after all. "Speculative" is the word Brian Greene uses in regards to Smolin's theories.
Smolin uses the term "multiverse" to describe the matryoshka-like existence beyond our one universe. He also describes evolution and natural selection in terms of the birth and engendering of universes, and in discussing such farflung cosmological thoughts, he delves into the nature of time itself.
Greene's book, in explaining the workings of the universe, delves deeply into the nature of subatomic parts. String theory (or superstring theory) holds that electrons, photons, and gravitons are composed of strings and membranes vibrating in ten (or, in the case of 11-D supergravity, a branch of M-theory, eleven) dimensions. We are familiar with, because we can perceive, only three spatial dimensions. Greene characterizes time as a dimension as well, because of the way he defines "dimension." Greene defines dimensions as those attributes necessary to communicate or define the precise location of an object or event.
For example, if I wanted to pinpoint the exact location of a meeting between Greene and Smolin, I would need to use four attributes. I assume they have met or will meet at some location on the earth's surface. So I need to specify (1) the latitude and (2) the longitude of the location of the meeting. If they meet in a building with more than one floor, I also need to specify (3) the elevation. But if you go to that precise spot 15 minutes after reading this article, you won't necessarily witness their meeting - because you also need to know (4) the date and time of the meeting. So in this sense we need four "dimensions" to pinpoint the meeting.
So what's up with those other dimensions, you may ask. While our three spatial dimensions are spread out vastly, and while our dimension of time is unidirectional, the other six or seven dimensions are curled up really really small. I may be stating things improperly to say that the size of those curled-up dimensions is called "the Planck length" and measures 10 to the -33 power centimeter (a millionth of a billionth of a billionth of a billionth of a centimeter). Greene compares the size of the Planck length to the size of an atom by comparing the size of a tree with the extent of the known universe. Pretty darned minuscule.
The thing that's hard for me to imagine in regards to those tiny curled-up dimensions is how they can be tiny and curled-up, yet everywhere in the extended spatial dimensions at the same time. If a dimension is tiny and curled-up, how can it be over here by my right pinky typing the "p" in "pinky," and yet also be simultaneously over there by the computer monitor, several inches away?
The reason it's important to understand how subatomic parts work is because that helps us understand what the universe was like shortly after the big bang. And understandings like that help us understand what universes, dimensions, and time are. Work on such matters is ongoing. Thanks to the internet, much more informed articles than this one are at your fingertips and easy to find. Just Google any of the terms in this article (except, perhaps, "pinky" or "wacky").
** To those sharp-eyed readers who noticed that I preceded this article with an "Afterword," and followed it with a "Forward" (as opposed to a "Foreword") are to be congratulated. It was purely intentional, and I imagine that those who noticed will understand the intention.