The Big Bang Theory & What Many Get Wrong
By Jon Therkildsen, MSc MBA from University of Århus (2004)
THIS ARTICLE WILL ADDRESS AND ANSWER THE FOLLOWING:
WHAT IS THE BIG BANG?
WHO GOT THE IDEA FIRST?
WHAT WAS BEFORE THE BIG BANG?
WHAT IS A SINGULARITY
WHAT IS OUTSIDE OF OUR UNIVERSE?
WHY DO WE SAY THE BIG BANG HAPPENED EVERYWHERE?
HOW DOES THE UNIVERSE END?
WHAT EVIDENCE IS THERE TO SUPPORT THE BIG BANG?
The cosmological model, dubbed ”The Big Bang” by a provocateur wordsmith 70 years ago, describes the historical development of the universe. Albeit commonly understood to show this, it does not say that the Universe had a beginning, it does not say it created everything, and it does not say it came from nothing — all quite resistant and popular misconceptions about the Big Bang, but misconceptions nonetheless.
The model is often unjustly elevated to the status of philosophical or religious dogma, when it is, at its core, a wholly honest and straightforward model.
I will try to clarify some of the misunderstandings below.
IT IS NOT A THEORY
There is no Big Bang Theory. Yes, that is right. Indeed, we have a popular TV show by that title, and the phrase often survives the editor’s notes and finds itself in headlines or in articles. However loud it may sound, there is simply not a Big Bang “Theory.”
There is a so-called model of cosmology that posits a situation leading to a historic point in cosmic time, where the conditions surrounding energy and matter must have been undergoing extreme expansion. Nevertheless, it is a model, or rather a collective prediction born from a bunch of other theories. It is not a theory in and of itself. It is a consequence, so to speak.
The strength of a model comes from the collective body of scientific theories that lead to it. To challenge such a model, one must dismantle where each of its leading theories is in err. And the truth is, in this case, the strength is tremendous. Not only in terms of cosmology and predicted evidence, but in multiple other fields and areas across the board, and for multiple other naturally confirmed phenomena as well.
The primary theories that gave us this model of modern cosmology are “The General Theory of Relativity,” “Quantum Field Theory” (via “The Standard Model of Particle Physics”), “Friedmann Equations,” the “Hubble–Lemaître law,” and “The Laws of Thermodynamics.” It is somewhat of a disservice to mention just these champions, as it is truly a collection of many theories, theorems, and other models.
The actual scientific title today is “the cosmological inflation model” or just “the cosmological model” and is, in more recent papers, sometimes called the Λ-CDM Model (Lambda Cold Dark Matter Model). No “Big Bang Theory” here.
IT WASN’T GEORGES LEMAITRE WHO WAS FIRST?
It is often stated that a Catholic priest, Georges Lemaître, was the first to formulate the Big Bang model in scientific terms, but this is not the case.
The idea that our universe had a beginning blast (a big bang event) comes from the Russian physicist and mathematician Alexander Friedmann and his excellent work on The General Theory of Relativity, published in 1922. He proposed three models for our universe’s history (and future development), all of which sprang from an energetic beginning. One of which aligns well with our current cosmological model.
Independent of Friedmann’s work, Georges Lemaître had a similar realization published in 1927 - five years later. Although known as a clergyman, he was an excellent scientist; whereas Friedmann was primarily a mathematician, Lemaître was foremost a cosmologist. Einstein knew of both these ideas, and he rejected them - something he told them in person. Later, he apologized to Friedmann, accepting that the math was impeccable, while incorrectly maintaining that the models were not naturally applicable. Lemaître was discouraged by Einstein’s initial resistance to this idea (and further, he learned from Einstein that Friedmann had been there before him). Unfortunately, illness took Friedmann before he could see the fruits of his labor… Luckily, not so for Lemaître. Still, the one who did the work first was Alex, not George.
It wasn’t until Edwin Hubble and his cosmic observations supporting an expanding (and thus a beginning) universe that the idea got wind. His observations started surfacing in 1929. Einstein finally caved in and accepted this truth in 1931 (which is ironic, as this is what his theories of relativity had predicted from the beginning).
Had Friedmann still been alive, I am sure he would have received a second apology.
IT WAS NOT “BIG,” AND THERE WAS NO “BANG”
This model has been discussed for about 100 years now, and many other models have been proposed, suggesting different conditions or cosmic histories. All of which have faded away. The astronomer, Fred Hoyle, opposed the Big Bang model until his death in 2001, and he is the one who coined the phrase “The Big Bang” back in 1949. He named it like that to ridicule it. He was wrong in his critique, but he was successful in his ridicule because the name stuck, sadly.
I say “sadly” because the label is imprecise and not very informative. There was no “bang” in any classical meaning of the word, and implying the initial inflation was an explosion is misleading, as it assumes a surrounding medium. The model encompasses all observations, including the very space that came from it. From a certain point of view, it did not expand into anything. Also, it was not ”big” in size either - even after the initial inflation had passed.
At best, we can say the universe came to be via an unimaginable burst of extreme expansion, otherwise known as the inflation of the universe. Space (and time) expanded rapidly, at least doubling its size many times over - from the size of a subatomic particle (in its beginning) to the size of a meatball - almost instantly (faster than the speed of light). However, even if the change was immense, it was not “big” in absolute terms; the size of a meatball is, after all, just the size of a meatball.
This expansion continues to this day, although at a much slower rate. Today the universe is big, but then it was not.
For the first 380 000 years after the initial inflation, the universe was too hot and dense for light to shine; it consisted of plasma - an opaque sea of protons, neutrons, and electrons. Sort of like a fog of energy and matter, if this can be imagined? Another 400 million years would pass before our universe began to form into what we can recognize today, but it still took another 9 billion years before our Solar System saw its first light. And then another 4.5 billion years for our Earth to be the home we see today.
The age is estimated to be about 13.8 billion years. However, since the beginning of the expansion of the observable universe, the size of the observable universe is estimated to be about 47 billion light-years in every direction we look today. The most straightforward explanation as to why it is not half of 13.8, for example, is that the expansion keeps expanding - and at tremendous speeds. When we observe light 10 billion years away, it has traveled at least 10 billion years more since it was emitted toward us. Observed light tells us where it was, not where it is - however, we can calculate where it is/where it would be. Compute the numbers, run the models, and the observable (the calculable) universe is presently estimated to be around 94 billion light-years across today. All of which began its travel 13.8 billion years ago.
The Big Bang was not a big bang. It was a rapid inflation or an incredible expansion - from a single point to the size of a meatball to everything we see today. A more befitting label would have been “The Quick Inflation”; not quite as catchy, though.
IT WAS NOT THE BEGINNING
In simplistic terms, the conditions behind what is popularly known as the Big Bang arise from extrapolating the current expansion of the cosmos backward in time. Just as we can foresee how the universe will look billions of years from now, or tomorrow, so can we extrapolate back in time and see how it looked yesterday, the day before that, etc. Compute the numbers, and measure the observations, and it shows our observable universe was highly concentrated about 13,8 billion years ago, into an extremely hot and dense space.
The model leads us to a point where we can see no further back, and it leads us to a point where all the observable matter and energy in our universe was in a singular point. However, none of the theories say or even attempt to say what was further back. Or for how long has this point existed?
A bit like a deflating balloon.
At one point the balloon can deflate no more.
Even the theories on which the model is built do not quite agree here. General relativity predicts a singularity at the moment 13.8 billion years ago. This point is not to be understood as a compressed sea of particles. It is a singularity: A place where our knowledge does not comply anymore, and so a ”sea of particles” is not (or cannot be) applicable. It was a wobbly, absolute, indefinable space horizon. Whatever it was, we know it cannot be something that we know - if that makes any sense?
This is hard to accept, and fair enough. In real life, no physicists take it seriously, either, because a singularity is where our knowledge breaks down or fails. Our equations take us to a point right after this singularity, but no further and not “on” the singularity. We cannot scientifically say any more than that. It is not very sexy or exciting, perhaps, but it is a fact.
Was it a beginning?
Was it the beginning?
Was it an old existing space horizon?
Was it just one occurrence in a vibrant already exotic Universe?
We do not know. Moreover, and what is often missed in the public debate, the Big Bang model does not concern itself with these questions.
But there is hope. We may be able to figure it out still, but to do this, we need first to formulate the so-called “Theory of Everything” that combines “Quantum Mechanics” with “General Relativity” - this we do not have yet. Once we crack it - and we will - our equations will be able to take us further back still. But until we crack this nut, we do not know what occurred before, and one cannot positively assert that the Big Bang event was the actual beginning. In all likelihood, it wasn’t.
“A SINGULARITY in cosmology represents a point where the equations (or theories) break down. In essence, when general relativity concludes in a SINGULARITY, it tells us something is amiss. Since the Big Bang concludes in a SINGULARITY, we know, the model err. What is more, we know this error arises because the model does not combine quantum mechanics and the force of gravity into a single theory. To solve this “singularity conundrum,” we need a master unifying theory, a so-called “theory of everything” that combines all four fundamental forces. This, we do not have yet. So, until we crack this nut, anything that predicts a SINGULARITY predicts a point where it is at fault - which is why the Big Bang model can say nothing about what was before it, except that it was something our current equations cannot properly describe. The model is limited to the point 13.8 billion years ago.”
IT IS NOT THE WHOLE UNIVERSE
The Big Bang model concerns the observable universe and not the whole Universe - whatever it may be.
The thing about science is that its conclusions are based on observations and observations alone. When you read about the Big Bang in popular media and how it all began billions of years ago by creating space and time and everything, it is, in actuality, referring to the observable part of the Universe only. Not the whole Universe.
Now, the dogmatic scientist may say that all there is is what we can observe. He has a point because we know nothing beyond that. However, it does not mean there isn't something beyond that. There may be; we just do not know. And nor does the cosmological model claim there isn't.
“The observable universe” (lowercase "u") concerns everything we can observe and calculate. Our observable universe is at least 13.8 billion years old and measured to be about 94 billion light-years across in size.
“The Universe“ (capital "U") concerns Everything: The observable universe, the un-observable universe, parallel worlds, many worlds, hyperspace, multiverses, etc. Infinite or near-infinite in size.
Our understanding of the reality, of which we are a part, suggests that the Universe is infinitely bigger than the parts we can observe and measure. But it only suggests it. We have limited knowledge of it, except that logic and quantum-mechanical paradoxes suggest that much more lies beyond our immediate sphere.
IT DID NOT COME FROM NOTHING
Although the Big Bang model is commonly believed to say that the universe came into existence from nothing, it does not actually say so. It should be clear by now that the Big Bang model only takes us back in time to a point right after the initial singularity. It says nothing about what was before.
In the General Theory of Relativity, the observable universe is viewed as a geometric coordinate system consisting of four dimensions. Everything we see is within this coordinate system. Three dimensions are spatial and one temporal (often referred to as “time”). The Big Bang model then considers this coordinate system to have been highly compressed 13.8 billion years ago. Since everything we can observe today sprang from that moment in time (aka the big bang event), we can say, from a certain point of view, that everything began then - including this coordinate system of our space and our time. This, however, does not mean all of space and all of time began then, only our spacetime.
The General Theory of Relativity, as it is with most other theories, concerns the observable universe. Not the whole Universe, whatever it may be, and this is the point often missed.
Out there, somewhere, we may have similar or even vastly different types of coordinate systems - each with its own set of space-dimensions and time-dimension as well. We cannot say with any certainty because our observations and equations do not yet permit us to peek there. Even though our universe seems to have a finite existence, with the beginning of our time and our space, the whole Universe has, perhaps, been eternally present: A Universe with possibly endless smaller “bubble” universes, not unlike ours - popping in and out of existence.
Below is an artist's rendition of a bubble multiverse. Each bubble has its own coordinate system and spacetime dimensions. Such illustrations help to better understand why the observable universe need not be the final one. We may be one bubble amongst a sea of other bubbles - all of which have their own “time” and ”space.” Alas, we do not know whether this is the case, but no theory rules it out, and some suggest it may be.
In essence, the only thing we do know is that we do not know, and this is what a scientist can say. And whatever it was before the Big Bang event, it cannot be described by our current equations and observations - and this makes “nothing,” for example, an extremely unlikely candidate. For one, “nothing” can be described by our equations, and so by definition, whatever it was, it cannot be nothing or anything else we know of. Likely, it is an as-yet-unknown category-compression of mass, a form of conception of exotic matter, or other logical continuations of our current understandings.
Nevertheless, not knowing does not mean knowing it is not.
Furthermore, our knowledge of quantum fields and quantum mechanics has experimentally confirmed that “nothing” or “empty” is not as empty as many seem to believe. Once we crack the nut of successfully combining the laws of gravity with the unified theory of the three other fundamental forces, then we will have a scientific tool to go further back than what is possible under our current model of cosmology.
“In cosmology, there is a difference between “nothing” and “not something”. One must realize these words are mere inaccurate attempts to prose accurate equations. Take this example:
2 – 2 = 0 = 2 – 2
0 here is not “not something.” It is, in actuality, something. It is 2–2. And, in this equation 2–2 equate to 0, which is nothing… but not “not something”. Even 0 is not necessarily 0, as the above equation shows. This is a point often missed in the public debate about how quantum mechanics tells us particles can pop into existence out of apparently “nothing.” It can because “nothing” is not “not something.” Confusing? Fair; one reason why mathematics and not English is the preferred language of nature. The take away here is that nature [as described by Quantum Field Theory] does not have “not something”, it sometimes has nothing, which is always something.”
WE HAVE MANY IDEAS OF WHAT PRECEDED IT
I hope by now it is somewhat clear that to maintain the universe may have come from literally “nothing” is absurd. There are many scientific concepts proposing histories of what came before, such as the bubbleverse, hyperspace, multiverse conceptualizations, the outreached consequences of the 7 string theories, or the membrane theory. Although few agree, none of them assume that we came from nothing. And all of them assume there was something!
Professor Max Tegmark of MIT is an authority in the field of multiverses, and he has defined or summarized at least four different levels or classes of the Universe as a whole:
I: Infinity: A generic prediction of the cosmological inflation model, as an infinite ergodic universe, which contains Hubble volumes realizing all initial conditions - including an identical copy of you about 10^10^29 meters away - an endless universe, has unlimited (multiple) versions of itself. Simply said, there are regions of space that are too far away for us to have seen yet. Our observable universe might be 94 billion light-years across but fare long enough, and we will meet other universes. Even further, we will eventually find similar and identical to ours. Such is the nature of infinity. In an infinite universe, eventually, nature will create identical copies of you an infinite number of times. Each of the universes is physically the same as ours - the differences are due to variations in the initial arrangements of matter.
II: Bubbleverse: In many models, inflation can produce multiple Level I multiverses that have different physical constants, dimensionality, and particle content. Aka bubble universes (as in the illustration above). Each universe is a bubble among a sea of other universes. Each bubble will have its own time and its own space. Between the bubbles, we have hyperspace, an indefinable space, or a master-type space. All our observations thus far are within our own bubble, but much of our data analyzing the cosmic background radiation supports the notion of a bubbleverse out there. The Big Bang event started our little bubble, and there are many other Big Bang events throughout this “sea” constantly creating new bubbles. Quantum fields cause space to expand rapidly. In the bulk of space, random fluctuations prevent the field from decaying away; these fields lose their strength, and the expansion slows down. Those regions become bubbles.
III: The Many-Worlds of quantum mechanics: In unitary quantum mechanics, other branches of the wave-function create parallel universes constantly and near infinitely. For every subatomic action, in our reality, a parallel world is created (or split off), in which the opposite action is made. In time, the number of parallel worlds grows exponentially and increasingly discordantly. Your path in history is one, among many others, slightly different paths. In this Universe, there will be many versions of you. One where you marry “the one that got away,” and one where you did not. Such many worlds are located elsewhere, not in ordinary space but in an abstract realm of all possible states. Every conceivable way that reality may be (within the mechanics of the quantum realm) corresponds to different worlds. The many-worlds make their presence known in real-life experiments, such as wave interference (observer effects) and quantum computations.
IV: Mathematical Multiverse: Our universe is not only described by mathematics — it is mathematics. Other mathematical structures give different fundamental equations of physics. Essentially, a mathematical existence equals a reality. When our external physical reality is assumed to be purely mathematical, it opens up to other physical realities of different mathematical structures. This weltanschauung solves several scientific conundrums, and it fits well into many of our models of reality. To delve deeper into this idea, this paper is a good start.
V: The Simulation Hypothesis (This is not Tegmark; it is attributed to Professor Nick Bostrom of Oxford University, but when talking about multiverses, it qualifies): It fits under Tegmark’s level IV. The hypothesis is based upon one observation and one assumption:
We create computer simulations all the time. In games, in entertainment, and in research. Any given university runs hundreds of simulations every day to test out scientific hypotheses. The simulations get better and better.
It stands to reason that we will, in time, as IT improves, be able to create a virtual simulated reality so real that it will be near indistinguishable from our own reality - be it 50 years from now, or a thousand years from now.
The logical deduction from the above two points is that, in time, we will create a computer simulation that emulates our universe to the point of creating a computer simulation of itself. And so it continues; simulations are creating simulations, ad infinitum. The logical conclusion of the above consequence is that there will be exponentially more simulations of simulations than simulations we have created ourselves. In other words, logically, the world will consist of a near-infinite number of simulations of “our” reality. Probabilistically (logically), our current reality must be one of these simulations right now, as the base reality (the first one) is a mere one in near-infinity. The chance that we are in this base reality now is near zero. If the Simulation Hypothesis holds, our reality was created on a computer.
Each of these levels or classes above is not fantasy but are derived from proven and well-established theories (except number V, which is purely assumption-based logic), and each has several strong indicators of evidence to support them. It is science, and though perhaps not yet conclusive, it is not science fiction. They are all different and reasoned differently, but not exclusively. They could all be true. And all of them far exceed what The Big Bang model cover.
The takeaway here is that The Big Bang model fundamentally does not talk about an uncaused beginning. It does not even take us back to a ”bang.” We do not know what caused it - however, with our knowledge of the quantum realm, I will say we can infer it certainly was not an un-cause.
In conclusion; The Big Bang model is a consequence of our cosmological observations. Nothing more, nothing less. Not nothing.
WHY DO WE SAY THE BIG BANG WAS EVERYWHERE?
Imagine this piece of paper
1. Take a piece of paper, like the one above - just an ordinary piece of paper. Dot it with as many dots as you see fit.
This paper represents the universe, as we know it today. And the dots are the stars.
2. Crumble the paper into the smallest and tightest ball you can.
This ball represents the point just before what we call the Big Bang.
3. Now unfold this paper.
This unfolding is the history of the expansion of the universe. The un-crumbling ball of paper is our history happening - you started the inflation of the universe.
The universe becomes bigger and bigger (flatter and flatter) as you un-crumble it. Once the paper flattens as before, you have the universe as it is today.
The paper becomes the ball (the point before the Big Bang). The ball becomes the paper (The Expansion of the universe). The ball is the universe. The universe is the ball.
The Big Bang was everything. It is just flatter now.
Why do we see the famous background cosmic radiation everywhere? It was everywhere.
We do not know what lies beyond the ball a paper, and since we do not know, we usually say the ball is all. And scientifically, this is accurate; it is all we know. But we do not know everything.
HOW WILL THE UNIVERSE END?
There are four dominating concepts:
THE BIG RIP: Generally builds upon the notion that the expansion of the universe will continue increasing forever, even and eventually down to the subatomic level. So everything will, in the end, rip apart. By some calculations, this could happen in just 22 billion years.
THE BIG FREEZE, aka HEAT DEATH: Again, this is built upon the current expansion. However, in this scenario, the universe will continue to expand to the point where everything is so far apart that we all just slowly die out, or burn out. Perfect entropy. It will continue to get colder and colder until the temperature throughout the universe reaches absolute zero. Everything will be still - this one seems to have the most support.
THE BIG CRUNCH, aka THE BIG BOUNCE: This is a cyclic concept, unlike the others. Used to be the preferred model, but it is now dismissed by most. Anyway, after perhaps trillions of years, the average density of the universe is so immense that the expansion will come to a halt; the universe would begin the process of collapsing in on itself. Much like a rubber band would. Eventually, all matter in existence will be pulled back together into a singularity again. And we have the premise of a new Big Bang. Etc. Etc. Etc.
THE BIG SLURP: The nature of the Higgs boson could indicate that the vacuum of the universe is inherently unstable; it is in a so-called perpetual metastable state. If so, the universe may at one point (any point?) experience a cataclysmic event: A “bubble” from the multiverse, with a lower-energy state than ours, could be allowed to appear inside our universe. This would cause this “bubble” to expand rapidly, eating up everything in its way. Our universe would be annihilated entirely and suddenly, taken over by a new and possibly quite different one.
Cheers.
WHAT IS THE EVIDENCE BEHIND THE BIG BANG?
The evidence is primarily on three pillars. And the evidence is tremendous. The concept of the Big Bang has endured a century of ridicule and competing ideas, only to be verified again and again as data has poured in, especially over the last several decades. There is no better cosmological model supporting our observations and data today.
The expansion of the universe is deduced from the redshifting relationship of galaxies, as mapped by the “Hubble–Lemaître law”. Extrapolating backward in time, all matter in the universe was contained in a minuscule region of space. The logical consequence of the observed expansion leads us to a Big Bang event.
The abundances of the elements (hydrogen, helium, deuterium, lithium) are consistent with cosmological inflation and not with nucleosynthesis in stars. The abundances of helium and deuterium (stars only destroy deuterium) suggest their synthesis must have come from a Big Bang event.
The cosmic background radiation was predicted by the cosmological inflation model. The cosmic background radiation, with a wavelength dependence extremely close to a perfect blackbody, permeates the universe at 2.725 Kelvin. This is perfectly consistent with a Big Bang event in which the radiation field was in thermal equilibrium.
The figures below show how perfectly the theories predicted the distribution of the actual recorded data.
The green line in the above figures represents the theoretical predictions. The dots (and crosses) represent the recorded observations. The correlation is beautiful. Think about it for a minute. Predictions done by men and women fit nearly perfectly with cosmic observations across the universe, which is several billion years old. It is an incredible human achievement, even when we eventually formulate another cosmological model pushing further back and beyond the current horizon.
Hopefully, this model will be named by a friend, and not a foe.
Photos via Google