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What happened before the Big Bang?

An artist's interpretation of the Big Bang
An artist's interpretation of the Big Bang.
(Image: © Scott Wiessinger (USRA): Lead Producer Aaron E. Lepsch (ADNET): Technical Support Krystofer Kim (USRA): Lead Animator)

In the beginning, there was an infinitely dense, tiny ball of matter. Then, it all went bang, giving rise to the atoms, molecules, stars and galaxies we see today.

Or at least, that's what we've been told by physicists for the past several decades. 

But new theoretical physics research has recently revealed a possible window into the very early universe, showing that it may not be "very early" after all. Instead it may be just the latest iteration of a bang-bounce cycle that has been going on for … well, at least once, and possibly forever. 

Of course, before physicists decide to toss out the Big Bang in favor of a bang-bounce cycle, these theoretical predictions will need to survive an onslaught of observation tests.

Bouncing cosmologies

Scientists have a really good picture of the very early universe, something we know and love as the Big Bang theory. In this model, a long time ago the universe was far smaller, far hotter and far denser than it is today. In that early inferno 13.8 billion years ago, all the elements that make us what we are were formed in the span of about a dozen minutes.

Even earlier, this thinking goes, at some point our entire universe — all the stars, all the galaxies, all the everything — was the size of a peach and had a temperature of over a quadrillion degrees.

Amazingly, this fantastical story holds up to all current observations. Astronomers have done everything from observing the leftover electromagnetic radiation from the young universe to measuring the abundance of the lightest elements and found that they all line up with what the Big Bang predicts. As far as we can tell, this is an accurate portrait of our early universe.

But as good as it is, we know that the Big Bang picture is not complete — there's a puzzle piece missing, and that piece is the earliest moments of the universe itself.

That's a pretty big piece.

Related: From Big Bang to present: Snapshots of our universe through time

The conflagration

The problem is that the physics that we use to understand the early universe (a wonderfully complicated mishmash of general relativity and high-energy particle physics) can take us only so far before breaking down. As we try to push deeper and deeper into the first moments of our cosmos, the math gets harder and harder to solve, all the way to the point where it just … quits.

The main sign that we have terrain yet to be explored is the presence of a "singularity," or a point of infinite density, at the beginning of the Big Bang. Taken at face value, this tells us that at one point, the universe was crammed into an infinitely tiny, infinitely dense point. This is obviously absurd, and what it really tells us is that we need new physics to solve this problem — our current toolkit just isn't good enough.

Related: 8 ways you can see Einstein's theory of relativity in real life

To save the day we need some new physics, something that is capable of handling gravity and the other forces, combined, at ultrahigh energies. And that's exactly what string theory claims to be: a model of physics that is capable of handling gravity and the other forces, combined, at ultrahigh energies. Which means that string theory claims it can explain the earliest moments of the universe.

One of the earliest string theory notions is the "ekpyrotic" universe, which comes from the Greek word for "conflagration," or fire. In this scenario, what we know as the Big Bang was sparked by something else happening before it — the Big Bang was not a beginning, but one part of a larger process.

Extending the ekpyrotic concept has led to a theory, again motivated by string theory, called cyclic cosmology. I suppose that, technically, the idea of the universe continually repeating itself is thousands of years old and predates physics, but string theory gave the idea firm mathematical grounding. The cyclic universe goes about exactly as you might imagine, continually bouncing between big bangs and big crunches, potentially for eternity back in time and for eternity into the future.

Before the beginning

As cool as this sounds, early versions of the cyclic model had difficulty matching observations — which is a major deal when you're trying to do science and not just telling stories around the campfire. 

The main hurdle was agreeing with our observations of the cosmic microwave background, the fossil light leftover from when the universe was only 380,000 years old. While we can't see directly past that wall of light, if you start theoretically tinkering with the physics of the infant cosmos, you affect that afterglow light pattern.

And so, it seemed that a cyclic universe was a neat but incorrect idea.

But the ekpyrotic torch has been kept lit over the years, and a paper published in January to the arXiv database has explored the wrinkles in the mathematics and uncovered some previously missed opportunities. The physicists, Robert Brandenberger and Ziwei Wang of McGill University in Canada, found that in the moment of the "bounce," when our universe shrinks to an incredibly small point and returns to a Big Bang state, it's possible to line everything up to get the proper observationally tested result.

In other words, the complicated (and, admittedly, poorly understood) physics of this critical epoch may indeed allow for a radically revised view of our time and place in the cosmos.

But to fully test this model, we'll have to wait for a new generation of cosmology experiments, so let's wait to break out the ekpyrotic champagne.

Paul M. Sutter is an astrophysicist at SUNY Stony Brook and the Flatiron Institute, host of Ask a Spaceman and Space Radio, and author of Your Place in the Universe.

Originally published on Live Science.

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  • PaulDavidWolf
    The author jokingly uses Biblical terminology, but to me it is sad that instead of applying the scientific method to evidence, this field of pseudo-science is about proving the Biblical origin of the universe, which is in a steady state and had no beginning. This is what the evidence always shows. Yet the creationists never give up.

    The red shifts measured by Hubble (and more recently of supernovas) are ISOTROPIC. This would only be consistent with the big bang theory if the big bang occurred at the position of the observer. Otherwise, we could determine the location of the starting point of the big bang from the relative motion of the galaxies. Galaxies on the opposite side would be moving away from us, while galaxies on the same side would be moving in the same direction as us. Unfortunately, it has not been possible to determine the location of "ground zero," because the observed red shifts are ISOTROPIC. It doesn't make sense that they could be caused by the Doppler effect. Whatever is causing them, they tend to disprove, not prove, the big bang theory.

    When this is pointed out to believers, they may counter with another, abstract version of the big bang theory, which is that "space itself" is expanding uniformly like the surface of a balloon. There was, in fact, no great explosion, or ground zero where the big bang occurred. This abstract version was disproven by the Michaelson-Morley experiment. It is the same as arguing the medieval concept of the aether. "Space itself" cannot expand, because there is nothing there to expand. Moreover, Einstein's theory of special relativity means that the frame of reference is relative between the observer and observed. It would be hard to reconcile with the concept of an aether; ie., an "expanding universe" or universal frame of reference. This is a hidden flaw in any theory of an expanding universe, which implies a universal frame of reference that exists independently of the observer. To say nothing of how odd it is to choose a frame of reference that is changing over time. According to relativity, no frame of reference is preferred over any other.

    The other data used to argue the big bang theory, the presence of a nearly isotropic background of microwave radiation, suffers from the same problem. One wonders why the microwaves aren't all heading away from ground zero, the starting point for the big bang. Our own galaxy is racing away from ground zero at lightspeed - isn't this the basic idea of the big bang theory? The fact that the CMB is more or less isotropic tends to disprove that it originated in a big bang, just as the red shift data does.

    There is also something called the matter-antimatter symmetry problem. In the laboratory, matter and antimatter particles are always produced in pairs. If they come into contact, they annihilate each other, leaving only energy. The observed universe is made almost entirely of matter. If all matter was created from energy in a big bang, by what mechanism was it created, that did not result in the creation of an equal amount antimatter? There is no explanation, and no known mechanism.

    That's because the big bang theory is a creationist myth. It has already been disproven a dozen different ways. This multiple big bang theory also looks religiously motivated. Why else would anyone believe any of this?
    Reply
  • Stephen J. Bauer
    I agree with the article's premise that the concept of 'a Big Bounce' universe has similar problems with the concept of the 'Big Bang' universe. I especially agree with the assessment, "The main sign that we have terrain yet to be explored is the presence of a "singularity," or a point of infinite density, at the beginning of the Big Bang. Taken at face value, this tells us that at one point, the universe was crammed into an infinitely tiny, infinitely dense point. This is obviously absurd …". The concept of considering the 'Big Bang' theory from a singular point as modeled after a gravitational singularity, rather try thinking of the 'Big Bang' theory from a pre-existing fabric of space-time without any real matter, as a the proposed one dimensional determinant. Then start unfolding this dimensional perspective so space-time fabric into existence; first into a two dimensional space-time fabric, which is an expansion from our one dimensional space-time, and then into a three dimensional space-time fabric and so on. The expectation is that ordinary matter creation took place within a pre-existing medium of space-time. Indeed, the existence of ordinary matter would only warp the pre-existing fabric of space-time. Take away the positive density matter and you would still have a vessel in which the matter once existed. I would only be logical for the vessel to be one of dark energy; dark energy unaffected by this promulgation of matter.
    So if the 'Big Bang' expansion theory rubs you the wrong way, try thinking of the proposed one dimensional singularity as the pre-existing fabric of space-time without any real matter, rather than a singular point as modeled after a gravitational singularity . Then start unfolding it into existence; first into two dimensional space-time, which is an expansion from our one dimensional space-time, and then into a three dimensional space-time and so on. Therefore the universe is only expanding into its further evolution.
    Reply
  • Wanda
    admin said:
    The Big Bounce theory was once thought impossible. But two physicists have just resurrected it.

    What happened before the Big Bang? : Read more
    I have been struggling with these theories and concepts, but then again I am a civilian in the land of physics. I would dearly love to know how "our" universe and whatever went before ours and other universes got started, but I think I will need to have it spelled out in one-syllable words; I just hope I'm still alive when that explanation comes. I accept that I may never know, but I do not accept a "creator" theory (although I can understand why early big-brained humans would have needed to drum up such a story in order to cope with the viscitudes of their existences). As a minuscule grain of sand on one of the earth's dry spots, I almost wish that my brain were not big enough to ask such questions. But since I've asked, I hope the answers become available in my lifetime.
    Reply
  • YellowNumber5
    My favorite theory, based on the fact the universe is expanding beyond the point of any chance of a crush, is that between the consumption of black holes and the evaporation of matter into energy, that once matter no longer exists, the law of e=mc2 means time and space become infinite, essentially infinatim burgeoning the beginning of the next universe.

    Every new universe takes an infinity to produce.
    Reply
  • TorbjornLarsson
    Since Sutter is hedging with the need to test, I assume the claimed "resurrection" is a bit of a jest. The current inflationary big bang universe puts an indefinite period of cold inflation before the hot big bang, at energies that are orders of magnitude less than a presumed breakdown in general relativity. One can arguably speculate in the topology of a universe with a flat space since relativistic locally flat Minkowski space is silent on that - though flat space is the unconstrained, likely topology - but that would be no worse than "bounce" speculations.

    Two specific problems with a string bounce speculation would be string respectively bounce. String theory has natural scale - right above standard model of particles energy ranges - predictions of WIMPs and axions/axion like particles as well as natural scale electron asymmetries that hasn't shown up. Bounce theory (in general, but an advance on that would surely be remarked on) do not give the right entropy, it is ever increasing instead of initially zero.
    Reply
  • TorbjornLarsson
    PaulDavidWolf said:
    The author jokingly uses Biblical terminology, but to me it is sad that instead of applying the scientific method to evidence, this field of pseudo-science is about proving the Biblical origin of the universe, which is in a steady state and had no beginning. This is what the evidence always shows. Yet the creationists never give up.

    The red shifts measured by Hubble (and more recently of supernovas) are ISOTROPIC. This would only be consistent with the big bang theory if the big bang occurred at the position of the observer. Otherwise, we could determine the location of the starting point of the big bang from the relative motion of the galaxies. Galaxies on the opposite side would be moving away from us, while galaxies on the same side would be moving in the same direction as us. Unfortunately, it has not been possible to determine the location of "ground zero," because the observed red shifts are ISOTROPIC. It doesn't make sense that they could be caused by the Doppler effect. Whatever is causing them, they tend to disprove, not prove, the big bang theory.

    When this is pointed out to believers, they may counter with another, abstract version of the big bang theory, which is that "space itself" is expanding uniformly like the surface of a balloon. There was, in fact, no great explosion, or ground zero where the big bang occurred. This abstract version was disproven by the Michaelson-Morley experiment. It is the same as arguing the medieval concept of the aether. "Space itself" cannot expand, because there is nothing there to expand. Moreover, Einstein's theory of special relativity means that the frame of reference is relative between the observer and observed. It would be hard to reconcile with the concept of an aether; ie., an "expanding universe" or universal frame of reference. This is a hidden flaw in any theory of an expanding universe, which implies a universal frame of reference that exists independently of the observer. To say nothing of how odd it is to choose a frame of reference that is changing over time. According to relativity, no frame of reference is preferred over any other.

    The other data used to argue the big bang theory, the presence of a nearly isotropic background of microwave radiation, suffers from the same problem. One wonders why the microwaves aren't all heading away from ground zero, the starting point for the big bang. Our own galaxy is racing away from ground zero at lightspeed - isn't this the basic idea of the big bang theory? The fact that the CMB is more or less isotropic tends to disprove that it originated in a big bang, just as the red shift data does.

    There is also something called the matter-antimatter symmetry problem. In the laboratory, matter and antimatter particles are always produced in pairs. If they come into contact, they annihilate each other, leaving only energy. The observed universe is made almost entirely of matter. If all matter was created from energy in a big bang, by what mechanism was it created, that did not result in the creation of an equal amount antimatter? There is no explanation, and no known mechanism.
    That's because the big bang theory is a creationist myth. It has already been disproven a dozen different ways. This multiple big bang theory also looks religiously motivated. Why else would anyone believe any of this?

    Opinions may differ, I do not see any references to superstitious texts. Why would there be on a topic of science? While we are on the topic, creationism is theology, and precisely the theology you refer to. Such theologians are nominally what you claim others are.

    Speaking of science on the other hand, inflationary big bang is the accepted theory of the universe. Since you do not seem to know what it is about, let me first note that theory here is the original, science term that translates to fact if the theory is well tested - this one is. Second, I'm not going to motivate why this is the current science fact and theory, since you can see that in the nearest decent encyclopedia - it is general knowledge.

    On to particulars, that may be unknown to some: It is a misunderstanding to think of "big bang" as an explosion, it is simply the expansion in *every* volume that general relativity permit and which we see (from redshift, say). Let me repeat the observed facts: big bang is not an explosion, and the expansion is precisely as expected from a general relativistic universe: P1Q8tS-9hYoView: https://www.youtube.com/watch?v=P1Q8tS-9hYo, https://en.wikipedia.org/wiki/Friedmann_equations ]. (If the several senses of "big bang" confuses you, that should be a warning that you may misunderstand some of it. The "hot big bang" era is shown in the video, while another common definition is that the "big bang" era is the ongoing relatively low rate expansion era - inflation expansion rate was *huge*.) The video describes singularities as retired 40 years ago. And I don't think any scientists has ever entertained the notion that the expansion was an "explosion".

    It is funny that you raise the issue of matter/antimatter asymmetry - which is not considered urgent as inflationary big bang theory predicts so many observations - since there has been a huge inroad just last week. Neutrinos may suffice to explain the asymmetry https://www.sciencemag.org/news/2020/04/skewed-neutrino-behavior-could-help-explain-matter-s-dominion-over-antimatter# ].
    Reply
  • TorbjornLarsson
    Stephen J. Bauer said:
    I agree with the article's premise that the concept of 'a Big Bounce' universe has similar problems with the concept of the 'Big Bang' universe. I especially agree with the assessment, "The main sign that we have terrain yet to be explored is the presence of a "singularity," or a point of infinite density, at the beginning of the Big Bang. Taken at face value, this tells us that at one point, the universe was crammed into an infinitely tiny, infinitely dense point. This is obviously absurd …". The concept of considering the 'Big Bang' theory from a singular point as modeled after a gravitational singularity, rather try thinking of the 'Big Bang' theory from a pre-existing fabric of space-time without any real matter, as a the proposed one dimensional determinant. Then start unfolding this dimensional perspective so space-time fabric into existence; first into a two dimensional space-time fabric, which is an expansion from our one dimensional space-time, and then into a three dimensional space-time fabric and so on. The expectation is that ordinary matter creation took place within a pre-existing medium of space-time. Indeed, the existence of ordinary matter would only warp the pre-existing fabric of space-time. Take away the positive density matter and you would still have a vessel in which the matter once existed. I would only be logical for the vessel to be one of dark energy; dark energy unaffected by this promulgation of matter.
    So if the 'Big Bang' expansion theory rubs you the wrong way, try thinking of the proposed one dimensional singularity as the pre-existing fabric of space-time without any real matter, rather than a singular point as modeled after a gravitational singularity . Then start unfolding it into existence; first into two dimensional space-time, which is an expansion from our one dimensional space-time, and then into a three dimensional space-time and so on. Therefore the universe is only expanding into its further evolution.

    Several problems here, even if the generic sense is correct.

    First, and I think you say this as well as the opposite, a general relativistic universe may be empty.

    Second, and I think you say this, a general relativistic universe expansion depends on the inner state.

    Third, dark energy is likely the vacuum energy of the universe, which is the ground state of the matter and force fields. But the current vacuum energy became present only *after* matter was created in the hot big bang heating of the previously cold inflationary volume that now makes up our local universe. The previous potential energy of the inflation field was not its ground state, it was under slow roll towards lower energies. Actually the link to youtube I gave in another comment show some of these events.

    Fourth, space and time is and has always been 4D. It is the only geometry which has relativistic causality (signals) so has functional laws https://space.mit.edu/home/tegmark/dimensions.pdf ].
    Reply
  • Sopaconondas
    The doubt has no content, as before the Big Bang, there was the Nil, having this name as only content, also, time, a created element, as matter and energy, does not exist without matter and space.
    The Nil may be what Jesus called: 'The outer darkness' in the Gospel. 'The abyss', The fire Gehena', a Black Hole
    Reply
  • Stephen J. Bauer
    Wanda said:
    I have been struggling with these theories and concepts, but then again I am a civilian in the land of physics. I would dearly love to know how "our" universe and whatever went before ours and other universes got started, but I think I will need to have it spelled out in one-syllable words; I just hope I'm still alive when that explanation comes. I accept that I may never know, but I do not accept a "creator" theory (although I can understand why early big-brained humans would have needed to drum up such a story in order to cope with the viscitudes of their existences). As a minuscule grain of sand on one of the earth's dry spots, I almost wish that my brain were not big enough to ask such questions. But since I've asked, I hope the answers become available in my lifetime.
    Everyone is struggling with the same concepts and theories, which is why there are so many theories. However, no one can relate the answers to you; you have to work through it for yourself. The only true answer is one that can be experienced first hand; for you can never really believe an explanation that you cannot comprehend. And since that will not happen in our life time, there is only the after life to consider. It is rather a strange notion that we can only know the answers to what was before there was anything by discovering what will be. It has been said that the afterlife is the moment of infinity that is enlivened upon our passing into the astral plane. Within the astral plane, there is only the fifth dimensional perspective of all time and all space without time and space. While time continues for those trapped in the physical reality of spacetime, the afterlife stretches our moment of infinity through the connections of the living universe. As long as there is a universe, there is an astral plane upon which we can persist. And the universe will always exist in one form or another.

    But there is no need to rush because it as we can visit it upon our ability to enter into the astral plane, or just by participating in our own lucid dreams. While in this mode, one can view the physical realm of our fourth dimensional existence or strive for something greater. I've tried to capture my understanding of such a persistence in my 'Andrew Adventure' book series about the fictional realm of the Shadow-Forge. Or if you are more into a philosophical approach, there is my companion compendium series, 'The Evolutioning of Creation'. Both should keep your mind occupied while you work it out for yourself. As related in the book, 'Shadow-Forge Revelations': behest of my heart and my soul will follow.
    Reply
  • Stephen J. Bauer
    TorbjornLarsson said:
    Several problems here, even if the generic sense is correct.

    First, and I think you say this as well as the opposite, a general relativistic universe may be empty.

    Second, and I think you say this, a general relativistic universe expansion depends on the inner state.

    Third, dark energy is likely the vacuum energy of the universe, which is the ground state of the matter and force fields. But the current vacuum energy became present only *after* matter was created in the hot big bang heating of the previously cold inflationary volume that now makes up our local universe. The previous potential energy of the inflation field was not its ground state, it was under slow roll towards lower energies. Actually the link to youtube I gave in another comment show some of these events.

    Fourth, space and time is and has always been 4D. It is the only geometry which has relativistic causality (signals) so has functional laws https://space.mit.edu/home/tegmark/dimensions.pdf ].
    Interesting analysis - I cannot really argue with your logic. But what are the "several problems" to which you refer at the beginning of your reply?
    Reply