Before the Big Bang

Article written: 17 May , 2006
Updated: 19 Jun , 2013

Researchers have developed a model of a shrinking universe that existed prior to the Big Bang. Image credit: NASA. Click to enlarge
The Big Bang describes how the Universe began as a single point 13.7 billion years ago, and has been expanding ever since, but it doesn’t explain what happened before that. Researchers from Penn State University believe that there should be traces of evidence in our current universe that could used to look back before the Big Bang. According to their research, there was a contracting universe with similar space-time geometry to our expanding universe. The universe collapsed and then “bounced” as the Big Bang.

According to Einstein’s general theory of relativity, the Big Bang represents The Beginning, the grand event at which not only matter but space-time itself was born. While classical theories offer no clues about existence before that moment, a research team at Penn State has used quantum gravitational calculations to find threads that lead to an earlier time. “General relativity can be used to describe the universe back to a point at which matter becomes so dense that its equations don’t hold up,” says Abhay Ashtekar, Holder of the Eberly Family Chair in Physics and Director of the Institute for Gravitational Physics and Geometry at Penn State. “Beyond that point, we needed to apply quantum tools that were not available to Einstein.” By combining quantum physics with general relativity, Ashtekar and two of his post-doctoral researchers, Tomasz Pawlowski and Parmpreet Singh, were able to develop a model that traces through the Big Bang to a shrinking universe that exhibits physics similar to ours.

In research reported in the current issue of Physical Review Letters, the team shows that, prior to the Big Bang, there was a contracting universe with space-time geometry that otherwise is similar to that of our current expanding universe. As gravitational forces pulled this previous universe inward, it reached a point at which the quantum properties of space-time cause gravity to become repulsive, rather than attractive. “Using quantum modifications of Einstein’s cosmological equations, we have shown that in place of a classical Big Bang there is in fact a quantum Bounce,” says Ashtekar. “We were so surprised by the finding that there is another classical, pre-Big Bang universe that we repeated the simulations with different parameter values over several months, but we found that the Big Bounce scenario is robust.”

While the general idea of another universe existing prior to the Big Bang has been proposed before, this is the first mathematical description that systematically establishes its existence and deduces properties of space-time geometry in that universe.

The research team used loop quantum gravity, a leading approach to the problem of the unification of general relativity with quantum physics, which also was pioneered at the Penn State Institute of Gravitational Physics and Geometry. In this theory, space-time geometry itself has a discrete ‘atomic’ structure and the familiar continuum is only an approximation. The fabric of space is literally woven by one-dimensional quantum threads. Near the Big-Bang, this fabric is violently torn and the quantum nature of geometry becomes important. It makes gravity strongly repulsive, giving rise to the Big Bounce.

“Our initial work assumes a homogenous model of our universe,” says Ashtekar. “However, it has given us confidence in the underlying ideas of loop quantum gravity. We will continue to refine the model to better portray the universe as we know it and to better understand the features of quantum gravity.”

The research was sponsored by the National Science Foundation, the Alexander von Humboldt Foundation, and the Penn State Eberly College of Science.

Original Source: PSU News Release

11 Responses

  1. Cody says

    This is very interesting to me. It fits in a bit with what I have thought about the forming of the universe. If you will humor me a bit and read on I will tell you my thoughts. So first off the “Big Bang” was not the start of the universe just a cycle that has been going on forever. Also whatever size our universe is perceived to be is just say one drop in all our oceans. Black holes suck up matter at thousands or millions of locations and eventually compact so much they have to burst AKA “Big Bang” Massive energy released pushes everything apart and the unverse expands again. I think this has been going on forever. I have just read things like some stars measured are older than when the “Big Bang” ocurred and thought about how that could of happend. Well there is the view of an uneducated young man. Feel Free to tell me all the ways that I am wrong and have a nice day :).

  2. Paul says

    Cody. That’s what my theories would lead me to believe also. I’m also one with an amateur interest in this subject. One thing that I cannot get my head around, maybe because my brain isn’t capable of perceiving something without a beginning and end, is your point about this having been going on forever. And I guess this leads into a philosophical and potentially a theological debate as much as scientific, because science doesn’t know enough yet… What is forever? Surely we’re progressing along a timeline which must have started pre-big bangs * $. What was the start and if there was a start what was before that? Nothing? If so, then nothing is something. Probably all started from on atom, but then where did that come from and what surrounded it? I don’t think we’ll ever know. The only thing we know for certain is how miniscule we are in many ways, as individuals, as communities, as a civilisation, as a planet, a solar system, a universe and beyond and before…. In the words of Marty McFly, this is heavy stuff man.

  3. Mike says

    I have been reading much on this subject, but I can’t find a thoughtful answer to this: regardless of what preceded the big bang or big bounce, what would it have been like in that compressed mass just before it exploded? What forces would have been at work and how would they have been interacting with each other?

  4. Brad says

    My understanding is that space-time is non-existant prior to the big bang (bounce). And yet the model to describe the ‘singularity’ of whatever it is prior to the big bang always shows this tiny point floating in a space that cannot exist (yet). If there is no space or time then whence does this singularity reside? Can there be a point of matter/energy without space or time to describe its minute spatial dimension or its temporal duration? It seems that the limits of our own earthbound perception forces mental models that cannot comply with the actual cosmic condition prior to the creation of space-time. Even physicists are prone, it seems to me, to habituate their mental models, sublimated in terrestrial dimensions, to conform to a 3d or 4d space-time-energy model that exists after the fact of the big bang. Yes, I know that string theory postulates 9 dimensions. But that doesn’t nullify the argument. the number of dimensions is immaterial. So, if someone can describe the actual condtion of existence prior to its own creation, by whatever means, I would be most interested to read it and they would probably win the Nobel Prize for physics.

  5. Michael says

    That is a very stupid question to ask indeed! what was there before the universe. The answer is that there was no before the universe. When the universe was born, TIME, space and matter was born so the question is meaningless to ask.

  6. Jake says

    my view on the subject is that of course there was no time or space or universe before the big bang, or if there was then there has been a continual cycle of them for an almost infinite period of time.
    the difficult question is: when did this cycle begin?
    before there was “anything” i believe there was simply the vacuum of space. it is impossible to escape the mental constraint that it has been there infintely, but quite simply it must have as there is no other explanation. within this vacuum forces such as gravity and perhaps others we don’t know of were present (no need for them to have been created as a force is not material) and at point dot space was torn by these forces and an atom of space “tear” (hydrogen?) was created. the forces present would then react to this atom tearing it apart (like particle acceleration) and releasing vast amounts of energy into the empty vacuum. this energy then subjected to present forces would react in a certain way and would collapse in on itself before expanding once again. this process would continue until more matter is formed from the energy released and the first universe begins.

    to answer the question as to what was there BEFORE ‘anything’? – think of it as simply a big black vacuum of space, condensed like a black hole as the only thing present was gravity (or perhaps as mentioned other forces we do not know of) – and where did this space come from? well thats easy! its always been there!

  7. Onyidzin says

    Hi, Michael. I’m a lay-person with an interest in these issues, and I actually think that Brad’s question is a reasonable one. I’d be interested to see what you and Jake and others here think of the article about multi-dimensionality, at

    Even though a line in that article seems to suggest that some opinion is that time is a variable which all intelligent beings might experience, my humble opinion is that if we can accept that space can be curved and time can be stretched (sorry for non-tech terms) in the region of a black hole, then surely we can accept that thinking in terms of linear time when we contemplate pre-Big Bang phenomena, is not necessarily correct?

    Perhaps time is looped from a God’s-eye view?

  8. Michael says

    Well you know, I know that this a very tough to understand. Lots of people would agree. We know that the universe is 13.7 billion years old therefore time is also 13.7 billion years old. So if the universe has an age. what was there before it? there was nothing, there wasnt even such a thing as “nothing”. There is no simplier way to explain this because it is not discribable. This coming from my brain you wouldnt believe. You can raise a question at this website Those of you who know Patrick Moore, Brian May and Chris Lintott’s book called BANG! can ask them because it came from their minds.

    Another different question that has been raised is What is outside the universe? There is no outside the universe, space itself is only within the universe. Another thing that really confuses me is that the universe is FLAT! If you didnt know, long ago in the time of chris columbus, people use to think the earth was flat like a pancake, but it was actually not true because its round. Now when you gaze up to the stars and see the universe, it looks like a 360 degree dome (like a sphere) but actually its flat and not round. That is a very difficult picture to create in my mind indeed. Does anybody know about a flat universe we live in?

  9. Chad McKinley says

    I have been thinking on this subject as well recently and formulating a hypothesis based on my admittedly amateurish understanding of Physics.

    Imagine yourself rolling 2 dice. When the odd numbers come up count that as a negative, even numbers count as a positive. On average one will come up odd the other negative. The effects(+1+(-1)) cancel each other out. Most of the time this is true however sometimes you will “roll” 2 even numbers or 2 odd numbers. Sometimes you might get “lucky” and roll a streak of even numbers. Roll long enough and ultimately your steak will end and it will be followed by a streak of odd numbers. Mathematically the “law” of averages prevails.

    Now consider the above example in terms of Vacuum energy. Virtual pairs are spontaneously created and annihilate each other. They are called virtual because they don’t really exist until they interact with something in our universe such as a photon of light or 2 neutrally charged metal plates as in the Casmir experiment. This “vacuum energy is always neutral because the effect always cancels itself out, and does not violate the first law of thermodynamics.

    Now try and imagine what a universe where space and time are meaningless. The idea of before or after, up and down have no meaningful concept. Such is the point at the “moment of the Big Bang”. Space and Time can be both infinite and finite at the same time.

    In the above mentioned example of dice being rolled on infinite scale guarantee’s you will go on a streak rolling “even numbers a million, a trillion an infinite number of times. As the positive partials “fill” the void or singularity space expands, the continuing changing state of the universe defines time. Our Universe is one of those streaks if you will. Ultimately the universe will grow cold and decay back to nothingness. Space and Time will again become meaningless concepts because existence will again return to its(natural?) 0 point energy and the negative results will cancel out the previous positive results recreating the cosmic equilibrium of absolute nothingness.

  10. JTankers says

    Cosmological observations provide an incredibly rich set of clues to the pre-big bang universe. Do you see any flaws in: The pre-big bank universe at

    In the beginning (in the pre-big bang universe) there was only the vast vacuum of space and time. But this vacuum was not sterile, it was seething with vacuum energy. This vacuum energy field permeates and defines the universe, an astronomically large sphere of energy. And just as matter generates gravity by warping space and time, so does energy and this is the force that defines the size and shape of the universe, and also the force that bestows mass on matter…

    …When a virtual matter/anti-matter pair becomes a matter matter pair, the virtual particles are no longer able to mutually annihilate and they become real, stealing energy from the vacuum energy of space. This is the mechanism of slow matter creation in the first phase of the pre-big bang universe. Over perhaps a billion billion years, clouds of matter form over the entire universe, and eventually coalesce into cosmological bodies and eventually the first pre-big bang black hole, which starts the second phase of the pre-big bang universe, fast accretion of matter from vacuum energy by black holes…

  11. King 16 says

    Let me tel you my idea! to support the idea here is a story. yesterday i saw a film. when film started a cartoon came and was wearing a black jacket. and when the film ended he was wearing green jacket.

    After that i though ok assume i dont know that this is a film. which is not true. i will start thinking about from where the cartoon came, how it was created, and before that what was there. and after film finished where the cartoon went. what ever amount of effort i put in i will not be able to see the cartoon before the film started and after the film ends. so where it came from..

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