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IF the universe is just an infinite loop of events from expanding to contracting does that mean all this has happened before? The initial conditions for the next big bang would (or rather could) be the same as ours which would result everything happening in the exact same way. I could be way off but it's really strange thinking all of this has happened "before" like the time of arrow is somehow looped and we're all living the same life over and over again without even realizing it.
The Big Bang Vs. Big Bounce Theory of the Universe
Nothing fascinates me more than the origin of our Universe. For years I wondered how it came about and once I was old enough to understand explanations such as the Big Bang, I was awestruck.
A concept that always nagged at me was the concept of universal expansion. My mind, even still, has trouble wrapping around the fact that the Universe isn’t expanding into anything, it’s just expanding. The concept under the Big Bange theory that space itself is flexible and that, rather than galaxies moving further from each other, the space between them is just increasing blows my mind.
I guess put into simpler words: the Universe is a mind-boggling mystery.
So, when I read about an alternative theory to the Big Bang that’s been gaining traction in recent years, I was quite surprised. Regardless of your belief in the context of the Universes origin, the novel Big Bounce theory is certainly food for thought.
Without further ado, let’s dive into examining these two competing theories…
Ask Ethan: How Well Has Cosmic Inflation Been Verified?
The quantum fluctuations that occur during inflation get stretched across the Universe, and when . [+] inflation ends, they become density fluctuations. This leads, over time, to the large-scale structure in the Universe today, as well as the fluctuations in temperature observed in the CMB. These new predictions are essential for demonstrating the validity of a fine-tuning mechanism.
E. Siegel, with images derived from ESA/Planck and the DoE/NASA/ NSF interagency task force on CMB research
So, you want to know how the Universe began? You're not alone. Every other curious member of humanity, for as long as recorded history exists (and probably much longer), has wondered about exactly this question, "where does all this come from?" In the 20th century, science advanced to the point where a large suite of evidence pointed to a singular answer: the hot Big Bang.
Yet a number of puzzles arose that the Big Bang was unable to solve, and a theoretical add-on to the Big Bang was proposed as the ultimate cosmic solution: inflation. This December will mark 40 years since inflation was proposed by Alan Guth, and Paul Erlich wants to know how well inflation has stood the test of time, asking:
To what margin of error or what level of statistical significance would you say you say inflation has been verified?
The short answer is "better than most people think." The long answer is even more compelling.
The redshift-distance relationship for distant galaxies. The points that don't fall exactly on the . [+] line owe the slight mismatch to the differences in peculiar velocities, which offer only slight deviations from the overall observed expansion. The original data from Edwin Hubble, first used to show the Universe was expanding, all fit in the small red box at the lower-left.
Robert Kirshner, PNAS, 101, 1, 8-13 (2004)
The Big Bang is an incredibly successful theory. It began from just two simple starting points, and made an extrapolation from there. First, it insisted that the Universe be consistent with General Relativity, and that is the theory of gravity that we should use as our framework for building any realistic model of the Universe. Second, it demanded that we take seriously the astronomical observations that galaxies, on average, appear to be receding from us with speeds that are in direct proportion to their distance from us.
The simplest way to proceed is to let the data guide you. In the context of General Relativity, if you allow the Universe to be evenly (or roughly evenly) filled with matter, radiation, or other forms of energy, it will not remain static, but must either expand or contract. The observed redshift-distance relation can be directly explained if the fabric of space itself is expanding as time goes on.
The balloon/coin analogy of the expanding Universe. The individual structures (coins) don't expand, . [+] but the distances between them do in an expanding Universe. This can be very confusing if you insist on attributing the apparent motion of the objects we see to their relative velocities through space. In reality, it's the space between them that's expanding.
E. Siegel / Beyond The Galaxy
If this is the picture of the Universe you put together, it can carry some enormous consequences along for the ride. As the Universe expands, the total number of particles within it remains the same, but the volume increases. As a result, it gets less dense. Gravity pulls things into progressively larger-scale clumps with the passage of more time. And radiation — whose energy is defined by its wavelength — sees its wavelength stretch as the Universe expands hence, it becomes cooler in temperature and lower in energy.
The huge idea of the Big Bang is to extrapolate this idea backwards in time, to higher energies, higher temperatures, greater densities, and a more uniform state.
After the Big Bang, the Universe was almost perfectly uniform, and full of matter, energy and . [+] radiation in a rapidly expanding state. The Universe's evolution at all times is determined by the energy density of what's inside it. If it's expanding and cooling today, however, it must have been denser and hotter in the distant past.
This led to three new predictions, in addition to the expanding Universe (which had already been observed). They were as follows:
- The earliest, hottest, densest times should allow for a period of nuclear fusion early on, predicting a specific set of abundance ratios for the lightest elements and isotopes even before the first stars form.
- As the Universe cools further, it should form neutral atoms for the first time, with the leftover radiation from those early times traveling unimpeded and continuing to redshift until the present, where it should be just a few degrees above absolute zero.
- And finally, whatever initial density imperfections are present should grow into a vast cosmic web of stars, galaxies, galaxy clusters, and cosmic voids separating them over the billions of years that have passed since those early stages.
All three predictions have been verified, and that's why the Big Bang stands alone among theories of the Universe's origins.
A visual history of the expanding Universe includes the hot, dense state known as the Big Bang and . [+] the growth and formation of structure subsequently. The full suite of data, including the observations of the light elements and the cosmic microwave background, leaves only the Big Bang as a valid explanation for all we see. As the Universe expands, it also cools, enabling ions, neutral atoms, and eventually molecules, gas clouds, stars, and finally galaxies to form.
But that doesn't mean the Big Bang explains everything. If you extrapolate all the way back to arbitrarily high temperatures and densities — all the way back to a singularity — you wind up with a number of predictions that don't pan out in reality.
We don't see a Universe with different temperatures in different directions. But we should, since a region of space tens of billions of light-years to your left and another one tens of billion of light-years to your right should never have had time to exchange information since the Big Bang.
We don't see a Universe with leftover particles that are relics from some arbitrarily hot time, like magnetic monopoles, despite the fact that they should have been produced in great abundance.
And we don't see a Universe with any measurable degree of spatial curvature, despite the fact that the Big Bang has no mechanism to exactly balance energy density and spatial curvature from an extremely early time.
If the Universe had just a slightly higher density (red), it would have recollapsed already if it . [+] had just a slightly lower density, it would have expanded much faster and become much larger. The Big Bang, on its own, offers no explanation as to why the initial expansion rate at the moment of the Universe's birth balances the total energy density so perfectly, leaving no room for spatial curvature at all. Our Universe appears perfectly spatially flat.
Ned Wright's cosmology tutorial
The Big Bang, on its own, offers no solution to these puzzles. It succeeds if we extrapolate back to a hot, dense, almost-perfectly-uniform early state, but it doesn't explain any more than that. To go beyond these limitations requires a new scientific idea that supersedes the Big Bang.
But superseding the Big Bang isn't easy at all. To do so, a new theory would have to do all three of the following:
- Reproduce all of the successes of the Big Bang, including the creation of an expanding, hot, dense, almost-perfectly uniform Universe.
- Provide a mechanism for explaining those three puzzles — the temperature uniformity, the lack of high-energy relics, and the flatness problem — that the Big Bang has no solution for.
- Finally, and perhaps most importantly it must make new, testable predictions that are different from the standard Big Bang that it's attempting to supersede.
The idea of inflation, and the hope that it could do so, began in late 1979, when Alan Guth wrote the idea down in his notebook.
It was the consideration of a number of finely-tuned scenarios that led Alan Guth to conceive of . [+] cosmic inflation, the leading theory of the Universe's origin.
What inflation specifically hypothesized is that the Big Bang wasn't the beginning, but rather was set up by a prior stage of the Universe. In this early state — dubbed an inflationary state by Guth — the dominant form of energy wasn't in matter or radiation, but was inherent to the fabric of space itself, and possessed a very large energy density.
This would cause the Universe to expand both rapidly and relentlessly, driving any pre-existing matter apart. The Universe would be stretched so large it would be indistinguishable from flat. All the parts that an observer (like us) would be able to access would now have the same uniform properties everywhere, since they originated from a previously-connected state in the past. And since there would be a maximum temperature the Universe achieved when inflation ended, and the energy inherent to space transitioned into matter, antimatter, and radiation, we could avoid the production of leftover, high-energy relics.
In the top panel, our modern Universe has the same properties (including temperature) everywhere . [+] because they originated from a region possessing the same properties. In the middle panel, the space that could have had any arbitrary curvature is inflated to the point where we cannot observe any curvature today, solving the flatness problem. And in the bottom panel, pre-existing high-energy relics are inflated away, providing a solution to the high-energy relic problem. This is how inflation solves the three great puzzles that the Big Bang cannot account for on its own.
E. Siegel / Beyond The Galaxy
All at once, all three of those puzzles that the Big Bang couldn't explain were solved. This was truly a watershed moment for cosmology, and immediately led to a deluge of scientists working to correct Guth's original model in order to reproduce all of the Big Bang's successes. Guth's idea was published in 1981, and by 1982, two independent teams — Andrei Linde and the duo of Paul Steinhardt and Andy Albrecht — had done it.
The key was to picture inflation as a slowly-rolling ball atop a hill. As long as the ball remained atop the plateau, inflation would continue to stretch the fabric of space. But when the ball rolls down the hill, inflation comes to an end. As the ball rolls into the valley below, energy inherent to space gets transferred into matter, antimatter and radiation, leading to a hot Big Bang, but with a finite temperature and energy.
When cosmic inflation occurs, the energy inherent in space is large, as it is at the top of this . [+] hill. As the ball rolls down into the valley, that energy converts into particles. This provides a mechanism for not only setting up the hot Big Bang, but for both solving the problems associated with it and making new predictions as well.
At last, not only did we have a solution to all of the problems that the Big Bang couldn't resolve, but we could reproduce all of its successes. The key, then, would be to make new predictions that could then be tested.
The 1980s were full of such predictions. Most of them were very general, occurring in practically all viable models of inflation that one could construct. In particular, we realized that inflation had to be a quantum field, and that when you have this rapid, exponential expansion occurring with an extremely high energy inherent to space itself, these quantum effects can have impacts that translate onto cosmological scales.
The fluctuations in the cosmic microwave background, as measured by COBE (on large scales), WMAP (on . [+] intermediate scales), and Planck (on small scales), are all consistent with not only arising from a scale-invariant set of quantum fluctuations, but of being so low in magnitude that they could not possibly have arisen from an arbitrarily hot, dense state. The horizontal line represents the initial spectrum of fluctuations (from inflation), while the wiggly one represents how gravity and radiation/matter interactions have shaped the expanding Universe in the early stages.
In brief, the six most generic predictions were:
- There should be an upper-limit to the maximum temperature the Universe achieves post-inflation it cannot approach the Planck scale of
The magnitudes of the hot and cold spots, as well as their scales, indicate the curvature of the . [+] Universe. To the best of our capabilities, we measure it to be perfectly flat. Baryon acoustic oscillations and the CMB, together, provide the best methods of constraining this, down to a combined precision of 0.4%.
Smoot Cosmology Group / LBL
It's now 2019, and the first four predictions have been observationally confirmed. The fifth has been tested down to the
0.4% level and is consistent with inflation, but we haven't reached the critical level. Only the sixth point has not been tested at all, with a famous false-positive detection appearing earlier this decade owing to the BICEP2 collaboration.
The maximum temperature has been verified, by looking at the cosmic microwave background, to be no greater than about 10 16 GeV.
Super-horizon fluctuations have been seen from the polarization data provided by both WMAP and Planck, and are in perfect agreement with what inflation predicts.
The latest data from structure formation indicates that these early, seed fluctuations are at least 98.7% adiabatic and no more than 1.3% isocurvature, consistent with inflation's predictions.
But the best test — and what I'd call the most significant confirmation of inflation — has come from measuring the spectrum of the initial fluctuations.
Correlations between certain aspects of the magnitude of temperature fluctuations (y-axis) as a . [+] function of decreasing angular scale (x-axis) show a Universe that is consistent with a scalar spectral index of 0.96 or 0.97, but not 0.99 or 1.00.
P.A.R. ADE ET AL. AND THE PLANCK COLLABORATION
Inflation is very particular when it comes to what sorts of structure should form on different scales. We have a quantity that we use to describe how much structure forms on large cosmic scales versus smaller ones: ns. If you formed the same amount of structure on all scales, n s would equal 1 exactly, with no variations.
What inflation generically predicts, however, is that we will have an n s that's almost, but slightly less than, 1. The amount we depart from 1 by is determined by the specific inflationary model. When inflation was first proposed, the standard assumption was that n s would be exactly equal to 1. It wouldn't be until the 2000s that we became capable of testing this, through both the fluctuations in the cosmic microwave background and the signature of baryon acoustic oscillations.
As of today, n s is approximately 0.965 or so, with an uncertainty of around 0.008. This means there's about a 4-to-5 sigma certainty that n s is truly less than 1, a remarkable confirmation of inflation.
Our entire cosmic history is theoretically well-understood, but only qualitatively. It's by . [+] observationally confirming and revealing various stages in our Universe's past that must have occurred, like when the first stars and galaxies formed, and how the Universe expanded over time, that we can truly come to understand our cosmos. The relic signatures imprinted on our Universe from an inflationary state before the hot Big Bang give us a unique way to test our cosmic history.
Nicole Rager Fuller / National Science Foundation
The Big Bang became our theory of the Universe when the leftover glow was discovered in the form of the cosmic microwave background. As early as 1965, the critical evidence had come in, enabling the Big Bang to succeed where its competitors failed. Over the subsequent years and decades, measurements of the cosmic microwave background's spectrum, the abundance of the light elements, and the formation of structure only strengthened the Big Bang. Although alternatives persist, they cannot stand up to the scientific scrutiny that the Big Bang does.
Inflation has literally met every threshold that science demands, with clever new tests becoming possible with improved observations and instrumentation. Whenever the data has been capable of being collected, inflation's predictions have been verified. Although it's perhaps more palatable and fashionable to be a contrarian, inflation is the leading theory for the best reason of all: it works. If we ever make a critical observation that disagrees with inflation, perhaps that will be the harbinger of an even more revolutionary theory of how it all began.
What Happened Before the Big Bang? How Our Primordial Standard Clock Could Help Test Cosmic Inflation
More than a century of scientific research has established the Big Bang model, often referred to as the standard model of cosmology, as the evolutionary theory of the observable universe. It describes in detail how the universe evolved from an extremely hot and dense state, when its age was less than a second, to the one we observe today, nearly 14 billion years later.
The Big Bang model is supported by key experimental evidence, including the expansion of space, the abundance of light chemical elements, and the remnant glow from the Big Bang that pervades all of space&mdashthe cosmic microwave background (CMB).
Using the Big Bang model, scientists can dial back in time and peek into the status of the universe at the moment of its creation. They found several mysterious puzzles. On the one hand, the infant universe was extremely uniform beyond reasonable expectation on the other hand, there were tiny irregularities&mdashwhose density contrast gradually grew under gravitational attraction and became the seeds of the galaxies&mdashthat exhibit very special patterns.
Both properties strongly suggest that the initial state of the Big Bang universe was the result of a very different epoch preceding it&mdashthe so-called primordial universe. This discovery started a four-decade long, and still ongoing, search for what happened before the Big Bang.
The leading candidate theory is cosmic inflation, which predicts that the primordial universe was dominated by some form of dark energy and expanded in an accelerated rate in a fleeting fraction of a second. The inflation scenario has become the most widely accepted theory. For many researchers, it provides the simplest explanation for the puzzles. And several predictions from the simplest inflation models have been verified by experiments measuring the properties of CMB and galaxy distribution.
However, a number of alternative theories have also been put forward, with some suggesting that the state of the universe before the Big Bang was contracting&mdashand the Big Bang was really part of a Big Bounce. These alternatives serve as eye-openers and reminders that several key predictions of inflation may not be unique to the inflation theory. There may be other ideas that need to be explored and tested.
Physics is an experimental science, and theories have to be tested by experiments. During the process, the issue of falsifiability&mdashthat is, whether a theory can be tested to be potentially shown wrong&mdashhas inevitably arisen.
Inflation theory is a large framework under which there are numerous models. The critics of inflation have pointed out that although some predictions of the simplest models match the observational results, there are also others that have been refuted&mdashagain by CMB experiments. In fact, there are so many different predictions from different models of inflation, it appears there are some that can explain the experiments, whichever way the experimental results go.
These controversies have been the subjects of active debates over the years, culminating in one in 2017 which involved more than 30 leading scientists including four Nobel Prize laureates and the late Stephen Hawking.
Testing inflation theory as a whole
In new work published in Physical Review Letters as an Editors' Suggestion, myself and two colleagues from Harvard University&mdashAvi Loeb, Chair of the Astronomy Department, and Zhong-Zhi Xianyu, a postdoctoral researcher of the Physics Department&mdashproposed how we could use the future experimental data to find out which theory is the correct one.
Our main goal is not to distinguish various models within the inflation theory, rather to test the inflation theory as a whole against the alternative frameworks.
In our view, inflation theory&mdashor any other alternative theory&mdashis more than just a mathematical framework which can be correct as long as it is self-consistent. The theory describes a physical process whose defining properties need to be tested and potentially falsifiable in experiments, like any other physical theories such as quantum mechanics or galaxy formation.
While the critics are right that inflation theory has not made falsifiable predictions against the above-mentioned alternative theories, it does not mean such predictions do not exist. In fact, each of these theories has a very clear defining property&mdashthe evolution of the size of the primordial universe. For example, during inflation, the size of the universe grows exponentially while for Big Bounce, the size contracts before the bounce. The conventional observable attributes people have proposed so far&mdashalthough valuable for distinguishing various models within a theory&mdashhave trouble distinguishing the different theories because they are not directly related to this defining property.
How can we retrieve the direct information about the evolution of the size of the primordial universe? We propose to use the signals generated by the "primordial standard clocks." These clocks are any types of heavy elementary particles present in the energetic environment of the primordial universe. They exist in any theory because they are building blocks of the unification theory, whatever it is and they oscillated at some regular frequency, much like the ticking of a clock's pendulum.
To explain how the primordial standard clocks work, let us use the following analogy.
About 100 years ago, the map of stars made by astronomers was still two-dimensional in nature, because it was challenging to figure out the distances of stars from us. This ignorance led to intense debates on questions such as: Is the sun at the center of the Galaxy? Are there stars beyond the Milky Way? These issues were not settled until the discovery of the "standard candles"&mdashthe type of stars whose absolute brightness is known. Using these standard candles, it is straightforward to figure out how far the stars are, because the further they are, the fainter the associated standard candles appear. Therefore, the standard candles helped turning a merged stack of 2D star maps into a 3D map.
Ticking clocks and time stamps
Our current knowledge about the evolution of the primordial universe is at a similar stage. Through observing distributions of CMB and galaxies which were seeded by the primordial irregularities, we have obtained a series of snap shots of what happened before the Big Bang&mdashlike the series of images in a roll of film frames.
Now, what we do not know is the time coordinates of these snap shots. Without any clock information, we do not know how to play the film. Should it be played forwardly or backwardly, fast or slow? This led to debates on questions such as: Was the primordial universe inflating or contracting? And how fast did it do so?
The ticking standard clocks put time stamps on each of these frames when the film was shot before the Big Bang. If we could observe these time stamps, we would know what this film is about.
These time stamps&mdashthat we call "clock signals"&mdashtake different patterns for different theories of the primordial universe. Predicting the detailed patterns and suggesting how they should be searched for is the main result of our paper. If a pattern of signals representing a contracting universe were found, it would falsify the entire inflation theory, regardless of what detailed models one constructs and vice versa for alternative theories.
However, we cannot predict the overall strength of the signals, which may be very weak and hard to detect. This means we will have to search in many different places. We have already started the search in the CMB and there are some interesting candidate signals. To test if they are genuine signals, we need more data from future observational projects on CMB and galaxy distribution. There are many experiments being planned in the next decade or two&mdashoriginally with other scientific goals in mind. With our proposal, these data will also be used to search for a direct answer to the question: what exactly happened before the Big Bang?
Dr. Xingang Chen is a theoretical cosmologist at the Harvard-Smithsonian Center for Astrophysics and a senior lecturer at the Astronomy Department of Harvard University.
The 'Big Bang' Argument for the Existence of God (1998*)
The evidence is in. There is now little doubt that our universe was brought into existence by a "big bang" that occurred some 15 billion years ago. The existence of such a creation event explains a number of phenomena including the expansion of the universe, the existence of the cosmic background radiation, and the relative proportions of various sorts of matter. As the theory has been refined, more specific predictions have been derived from it. A number of these predictions have recently been confirmed. Although this is a major scientific achievement, many believe that it has theological implications as well. Specifically, they believe that it provides scientific evidence for the existence of god. Astronomer George Smoot suggested as much when he exclaimed at a press conference reporting the findings of the Cosmic Background Explorer (COBE) satellite, "If you're religious, it's like looking at the face of god." Why? Because something must have caused the big bang, and who else but god could have done such a thing? Astronomer Hugh Ross in his book, The Creator and the Cosmos , puts the argument this way: "If the universe arose out of a big bang, it must have had a beginning. If it had a beginning, it must have a beginner." So beguiling is this argument that astronomer Geoffrey Burbridge has lamented that his fellow scientists are rushing off to join the "First Church of Christ of the Big Bang." In what follows, I will attempt to determine whether such a conversion is the most rational response to the evidence.
The Traditional First-Cause Argument
The problems with the traditional first-cause or cosmological argument for the existence of god are legion. Before we examine the merits of the big bang argument, it will be helpful to have them before us.
The traditional first-cause argument rests on the assumption that everything has a cause. Since nothing can cause itself, and since the string of causes can't be infinitely long, there must be a first cause, namely, god. This argument received its classic formulation at the bands of the great Roman Catholic philosopher, Thomas Aquinas. He writes:
Saint Thomas's argument is this:
The most telling criticism of this argument is that it is self-refuting. If everything has a cause other than itself, then god must have a cause other than himself. But if god has a cause other than himself, he cannot be the first cause. So if the first premise is true, the conclusion must be false.
To save the argument, the first premise could be amended to read:
But if we're willing to admit the existence of uncaused things, why not just admit that the universe is uncaused and cut out the middleman? David Hume wondered the same thing:
The simplest way to avoid an infinite regress is to stop it before it starts. If we assume that the universe has always existed, we don't need to identify its cause.
Even if the universe is not eternal (as the big bang suggests), 1' is still unacceptable because modern physics has shown that some things are uncaused. According to quantum mechanics, subatomic particles like electrons, photons, and positrons come into and go out of existence randomly (but in accord with the Heisenberg uncertainty principles). As Edward Tryon reports:
h where D E is the net energy of the particles and h is Planck's constant.) The spontaneous, temporary emergence of particles from a vacuum is called a vacuum fluctuation, and is utterly commonplace in quantum field theory.
A particle produced by a vacuum fluctuation has no cause. Since vacuum fluctuations are commonplace, god cannot be the only thing that is uncaused.
Premise 1, in either its original or its amended version, is unacceptable. But even if it could be salvaged, the argument would still not go through because premise 3 is false. An infinitely long causal chain is not a logical impossibility. Most of us have no trouble conceiving of the universe existing infinitely into the future. Similarly we should have no trouble conceiving of it existing infinitely into the past. Aquinas's view that there must be a first cause rests on the mistaken notion that an infinite series of causes is just a very long finite one.
Consider a single-column stack of children's blocks resting on a table. Each block rests on the block below it except for the block that rests on the table. If the bottom block were taken away, the whole stack would fall down. In a finite stack of blocks, there must be a first block.
In an infinite causal chain, however, there is no first cause. Aquinas took this to mean that an infinite causal chain is missing something. But it is a mistake to think that anything Is missing from an infinite causal chain. Even though an infinite causal chain has no first cause, there is no event that doesn't have a cause. Similarly, even though the set of real numbers has no first member, there is no number that doesn't have a predecessor. Logic doesn't demand a first cause anymore than it demands a first number.
Finally, even if this argument did succeed in proving the existence of a first cause, it wouldn't succeed in proving the existence of god because there is no reason to believe that the cause of the universe has any of the properties traditionally associated with god. Aquinas took god to be all-powerful, all-knowing, and all-good. But from the existence of the universe, we cannot conclude that its creator had any of these properties.
An all-powerful being should be able to create an infinite number of different universes. But we arc acquainted with only one. Maybe our universe is the only one the creator had the power to create. In the absence of any knowledge of other universes, we are not justified in believing that the creator is all-powerful.
Similarly, an all-knowing being should know everything there is to know about every possible universe. But our universe gives us no reason to think that the creator has this kind of knowledge. Maybe our universe is the only universe he knew how to make. Without further information about the cognitive capacity of the creator, we can't conclude that the creator is all-knowing.
Finally, a universe created by an all-powerful, all-knowing, all-good being should be perfect. But the universe as we know it seems flawed. It certainly doesn't seem particularly hospitable to humans. Clarence Darrow explains:
Every place on Earth is subject to natural disasters, and there are many places where humans cannot live. Insects, on the other hand, seem to thrive most everywhere. When the great biologist G. B. S. Haldane was asked what his study of living things revealed about god, he is reported to have said, "An inordinate fondness for beetles." If the Earth was created for us (as many theists, including Ross, believe), it certainly leaves something to be desired.
Not only might the first cause be something less than perfect, it might be something less than human. David Hume provides the following example:
This is a coherent account of the creation of the world. It is logically possible that everything in the universe came from the belly of an infinite spider. So even if there was a first cause, it need not have been god.
The Big Bang Argument
The big bang argument for the existence of god is supposed to succeed where the traditional first-cause argument fails. Let's see if it does. Ross's version of the argument goes like this:
Unlike the traditional first-cause argument, this argument is not self-refuting because it does not imply that god has a cause. If god had no beginning in time, he need not have a cause. Moreover, this argument doesn't deny the possibility of an infinite causal chain. It simply denies that the actual chain of causes is infinite. While this represents an improvement over the traditional first-cause argument, the big bang argument runs into difficulties of its own.
Premise 6 conflicts with quantum mechanics because, as we have seen, quantum electrodynamics claims that subatomic particles can come into existence through a vacuum fluctuation. These particles have a beginning in time, but they have no cause because vacuum fluctuations are purely random events. Such particles, then, serve as a counterexample to premise 6.
Premise 7 conflicts with relativity theory because the general theory of relativity claims that there was no time before there was a universe. Time and the universe are coterminous-they came into existence together. This finding of Einstein's was anticipated by Augustine who proclaimed, "The world and time had both one beginning. The world was made, not in time, but simultaneously with time." If there was no time before there was a universe, the universe can't have a beginning in time.
Ross tries to avoid this conclusion by claiming that although the universe did not have a beginning in time as we know it, it had a beginning in another time dimension, He writes:
Ross needs the premise that the universe has a beginning in time to arrive at the conclusion that the universe has a cause. But the general theory of relativity prohibits the universe from a having a beginning in its own time dimension. So he postulates a higher time dimension that is independent of and preexistent to the time dimension of the universe.
As confirming evidence for the existence of this higher time dimension, Ross cites the Bible:
Whether the Bible speaks of an additional time dimension for god, the general theory of relativity does not. It makes no mention of an agent that exists outside of the space-time continuum. God is not written into the general theory of relativity.
Ross's argument here is a transcendental one, in both the logical and the theological senses of the word. It goes like this:
This argument arrives at the conclusion that the universe has a beginning in time by assuming that the universe has a cause. But the big bang argument uses the premise that the universe has a beginning in time to arrive at the conclusion that the universe has a cause. So Ross is arguing in a circle. He is assuming that the universe has a cause to prove that the universe has a cause. Because Ross begs the question about whether the universe has a cause, he does not succeed in proving the existence of a higher dimensional time, let alone the existence of a transcendental god.
Even if Ross's argument were not circular, it would still be equivocal because it uses the words "time" and "cause" in two different senses. Ordinary time is one-dimensional because it flows in only one direction. Ross's hypothetical time is two-dimensional because it flows in an infinite number of directions, just as the lines on a plane point in an infinite number of directions. Cause, as ordinarily understood, requires a one-dimensional time because a cause must always precede its effects. (An effect cannot precede its cause.) In a two-dimensional time, however, the notion of precession or succession (before or after) makes no sense. So from the fact that the universe has a beginning in a higher time dimension, it doesn't follow that it has a cause (in the ordinary sense), and that is what must be shown in order for the argument to succeed.
Furthermore, Ross's appeal to the Bible is unwarranted. Before we can accept the Bible as a source of data, we need some reason for believing it to be true. Traditionally, the truth of the Bible has been justified on the grounds that god wrote it. But this approach is not available to Ross because the existence of god is what he is trying to prove. He cannot assume the existence of God to prove the existence of God. So lie can't appeal to the Bible for evidential support.
The claim that the universe has a cause is essential to the big bang argument. Premises 6 and 7 do not justify this claim, for neither of them is true. But the failure of these premises to justify that claim does not necessarily mean that it is false.
There are good reasons for believing that the universe does not have a cause, however. Edward Tryon and others have suggested that the universe is the result of a vacuum fluctuation. Ross considers this theory but rejects it on the grounds that a vacuum fluctuation the size of the universe could only exist for 10 -103 seconds, "a moment a bit briefer than the age of the universe." But this follows only if we consider mass-energy to be the only type of energy in the world. Tryon suggests, however, that there is "another form of energy which is important for cosmology, namely gravitational potential energy." If the total amount of gravitational potential energy in the universe is equivalent to the total amount of mass-energy, then the universe may have a zero net value for all conserved quantities. But if it does, then a vacuum fluctuation the size of the universe could exist for a very long time. Tryon summarizes his reasoning as follows:
So not only can subatomic particles be uncaused, so can the universe.
Premise 9 is also suspect because even if the universe has a cause, it need not be god. Like the traditional first-cause argument, the big bang argument tells us nothing about the nature of the creator. Specifically, it doesn't tell us whether he (she, it?) is all-powerful, all-knowing, or all-good. And the universe itself gives us no reason to believe that the creator has any of those qualities.
Ross's argument, if successful, would give us reason to believe that the creator is transcendent, at least in the sense that he exists outside of the normal time dimension. On the basis of scripture, Ross makes the further claim that God is a person. But if God is transcendent in Ross's sense, its hard to see how he can also be a person. Paul Davies explains:
Ross's god exists in a two-dimensional time -- like a plane -- in which be can travel an infinite number or directions." Thus Ross's god knows the future as well as the past. How such a being can plan, act, hope, or even think is a mystery. In the absence of an explanation of how such a being can be a person, Ross's claim is incoherent.
Not only does the cause of the universe not have to be god, it does not have to be supernatural. It has long been known that if the amount of matter in the universe is great enough, then the universe will someday stop expanding and start contracting. Eventually, all the matter in the universe will be drawn back to a single point in what has come to be known as "the big crunch." Since matter supposedly cannot be crushed out of existence, the contraction cannot go on indefinitely. At some point the compressed matter may rebound in another big bang. If so, the big bang would have been caused by a prior state of the universe rather than some external agency.
This bounce theory of the universe has fallen on hard times, however. In a paper entitled "The Impossibility of a Bouncing Universe," Marc Sher and Alan Guth argued that the universe is not mechanically efficient enough to bounce." In terms of mechanical efficiency, the universe appears to be more like a snowball than a superball. Moreover, recent estimates indicate that there is not enough mass in the universe to stop its expansion. So it is doubtful that the big bang was the result of a prior big crunch.
Although the universe as a whole may never contract, we know that certain parts of it do. When a star has used up its fuel, the force of gravity causes it to contract. If the star is massive enough, this contraction results in a black hole. The matter in a black hole is compressed toward a point of infinite density known as a "singularity." Before it reaches the singularity, however, some physicists, most notably Lee Smolin, believe that it may start expanding again and give rise to another universe. In a sense, then, according to Smolin, our universe may reproduce itself by budding off. He writes:
A collapsing star forms a black hole, within which it is compressed to a very dense state. The universe began in a similarly very dense state from which it expands. Is it possible that these are one and the same dense state? That is, is it possible that what is beyond the horizon of a black hole is the beginning of another universe?
This could happen if the collapsing star exploded once it reached a very dense state, but after the black hole horizon had formed around it.
What we are doing is applying this bounce hypothesis, not to the universe as a whole, but to every black hole in it. If this is true, then we live not in a single universe, which is eternally passing through the same recurring cycle of collapse and rebirth. We live instead in a continually growing community of "universes," each of which is born from an explosion following the collapse of a star to a black hole.
Smolin's vision is an appealing one. It suggests that the universe is more like a living thing than an artifact and thus that its coming into being doesn't require an external agent.
Smolin's theory has the advantage of simplicity over Ross's. Because it does not postulate the existence of any supernatural entities, it has less ontological baggage than Ross's. It also has the advantage of conservatism over Ross's theory. Because it doesn't contradict any laws of science, such as the conservation laws (which must be rejected by anyone who believes in creation ex nihilo), it fits better with existing theory. Other things being equal, the simpler and more conservative a theory, the better. The fewer independent assumptions made by a theory and the less damage it does to existing theory, the more it systematizes and unifies our knowledge. And the more it systematizes and unifies our knowledge, the more understanding it produces. Since Smolin's theory is simpler and more conservative than Ross's, it is the better theory.
Smolin's theory is also potentially more fruitful than Ross's because it is possible to draw testable predictions from it. But what if these predictions are not born out? Does that mean that we must embrace the god hypothesis? No, because our inability to explain a phenomenon may simply be due to our ignorance of the operative laws. Augustine concurs. "A miracle," he tells us, "is not contrary to nature but contrary to our knowledge of nature.
We would be justified in believing that an inexplicable event is the work of god only if we were justified in believing that a natural explanation of it would never be found. But we can never be justified in believing that, because we can't predict what the future will bring. We can't rule out the possibility that a natural explanation will be found, no matter how incredible the event. When faced with an inexplicable event, it is always more rational to look for a natural cause than to attribute it to something supernatural. Appealing to the supernatural does not increase our understanding. It simply masks the fact that we do not yet understand.
What's more, any supposed miracle could be the result of a superadvanced technology rather than a supernatural being. Arthur C. Clarke once said that any sufficiently advanced technology is indistinguishable from magic. So the seemingly inexplicable events that many attribute to god could simply be the work of advanced aliens. Erik von Däniken argues as much in his book Chariots of the Gods, where he claims that the wheel that Ezekiel saw in the sky was really a UFO. Explanations that appeal to advanced aliens are actually superior to explanations that appeal to supernatural beings because they are simpler and more conservative -- they do not postulate any nonphysical substances and they do not presuppose the falsity of any natural laws. If astronomers feel the need to join a church, they would do better to join the First Church of Space Aliens than the First Church of Christ of the Big Bang.
* Theodore Schick is Professor of Philosophy at Muhlenberg College in Allentown, Pennsylvania. This article was originally published in Philo , the Journal of the Society of Humanist Philosophers, and has been electronically republished here with the written permission of the Society of Humanist Philosophers.
 Thomas H. Maugh, "Relics of 'Big Bang' Seen for First Tillie," Los Angeles Times April 24, 1992, p. A30.
 Hugh Ross, The Creator and the Cosmos (Colorado Springs: Navpress, 1995), p. 14.
 Stephen Strauss, "An Innocent's Guide to the Big Bang Theory: Fingerprint in Space Left by the Universe as a Baby Still Has Doubters Hurling Stones," Globe and Mail (Toronto), April 25, 1992, p. 1.
 Thomas Aquinas, Summa Theologica (New York: Benziger Bros., Inc., 1947).
 David Hume, Dialogues Concerning Natural Religion , ed. Norman Kemp Smith (Indianapolis: Bobbs-Merril, 1947), pp. 161-62.
 Edward Tryon, Nature 246, December 14, 1973.
 Clarence Darrow, The Story of My Life (New York: Charles Scribner's Sons, 1932), pp. 419-20.
 Hume, Dialogues Concerning Natural Religion , p. 180.
 Augustine, The City of God (trans. Dods) 11.6.
 Ross, The Creator and the Cosmos , p. 76.
 Edward Tryon, "Is the Universe a Vacuum Fluctuation?"
 Ross, The Creator and the Cosmos , pp. 77f.
 Paul Davies, God and the New Physics (New York: Simon and Schuster, 1983), pp. 38-39.
 Ross, The Creator of the Cosmos , p. 81.
 Alan H. Guth and Marc Sher, "The Impossibility of a Bouncing Universe," Nature 302 (1983): 505-507.
 Lee Smolin, The Life of the Cosmos (New York: Oxford University Press, 1997), pp. 87-88.
What Happened Before the Big Bang?
Spreading through a bounce: A state that initially has small fluctuations (left) bounces and develops larger fluctuations (right). Time proceeds along the horizontal axis, with the volume plotted vertically. Credit: Martin Bojowald, Penn State
New discoveries about another universe whose collapse appears to have given birth to the one we live in today will be announced in the early on-line edition of the journal Nature Physics on 1 July 2007 and will be published in the August 2007 issue of the journal's print edition.
"My paper introduces a new mathematical model that we can use to derive new details about the properties of a quantum state as it travels through the Big Bounce, which replaces the classical idea of a Big Bang as the beginning of our universe," said Martin Bojowald, assistant professor of physics at Penn State. Bojowald's research also suggests that, although it is possible to learn about many properties of the earlier universe, we always will be uncertain about some of these properties because his calculations reveal a "cosmic forgetfulness" that results from the extreme quantum forces during the Big Bounce.
The idea that the universe erupted with a Big Bang explosion has been a big barrier in scientific attempts to understand the origin of our expanding universe, although the Big Bang long has been considered by physicists to be the best model.
As described by Einstein's Theory of General Relativity, the origin of the Big Bang is a mathematically nonsensical state -- a "singularity" of zero volume that nevertheless contained infinite density and infinitely large energy. Now, however, Bojowald and other physicists at Penn State are exploring territory unknown even to Einstein -- the time before the Big Bang -- using a mathematical time machine called Loop Quantum Gravity.
This theory, which combines Einstein's Theory of General Relativity with equations of quantum physics that did not exist in Einstein's day, is the first mathematical description to systematically establish the existence of the Big Bounce and to deduce properties of the earlier universe from which our own may have sprung. For scientists, the Big Bounce opens a crack in the barrier that was the Big Bang.
"Einstein's Theory of General Relativity does not include the quantum physics that you must have in order to describe the extremely high energies that dominated our universe during its very early evolution," Bojowald explained, "but we now have Loop Quantum Gravity, a theory that does include the necessary quantum physics." Loop Quantum Gravity was pioneered and is being developed in the Penn State Institute for Gravitational Physics and Geometry, and is now a leading approach to the goal of unifying general relativity with quantum physics. Scientists using this theory to trace our universe backward in time have found that its beginning point had a minimum volume that is not zero and a maximum energy that is not infinite. As a result of these limits, the theory's equations continue to produce valid mathematical results past the point of the classical Big Bang, giving scientists a window into the time before the Big Bounce.
Quantum-gravity theory indicates that the fabric of space-time has an "atomic" geometry that is woven with one-dimensional quantum threads. This fabric tears violently under the extreme conditions dominated by quantum physics near the Big Bounce, causing gravity to become strongly repulsive so that, instead of vanishing into infinity as predicted by Einstein's Theory of General Relativity, the universe rebounded in the Big Bounce that gave birth to our expanding universe. The theory reveals a contracting universe before the Big Bounce, with space-time geometry that otherwise was similar to that of our universe today.
Bojowald found he had to create a new mathematical model to use with the theory of Loop Quantum Gravity in order to explore the universe before the Big Bounce with more precision. "A more precise model was needed within Loop Quantum Gravity than the existing numerical methods, which require successive approximations of the solutions and yield results that are not as general and complete as one would like," Bojowald explained. He developed a mathematical model that produces precise analytical solutions by solving of a set of mathematical equations.
In addition to being more precise, Bojowald's new model also is much shorter. He reformulated the quantum-gravity models using a different mathematical description, which he says made it possible to solve the equations explicitly and also turned out to be a strong simplification. "The earlier numerical model looked much more complicated, but its solutions looked very clean, which was a clue that such a mathematical simplification might exist," he said. Bojowald reformulated quantum gravity's differential equations -- which require many calculations of numerous consecutive small changes in time -- into an integrable system -- in which a cumulative length of time can be specified for adding up all the small incremental changes.
The model's equations require parameters that describe the state of our current universe accurately so that scientists then can use the model to travel backward in time, mathematically "un-evolving" the universe to reveal its state at earlier times. The model's equations also contain some "free" parameters that are not yet known precisely but are nevertheless necessary to describe certain properties. Bojowald discovered that two of these free parameters are complementary: one is relevant almost exclusively after the Big Bounce and the other is relevant almost exclusively before the Big Bounce. Because one of these free parameters has essentially no influence on calculations of our current universe, Bojowald colludes that it cannot be used as a tool for back-calculating its value in the earlier universe before the Big Bounce.
The two free parameters, which Bojowald found were complementary, represent the quantum uncertainty in the total volume of the universe before and after the Big Bang. "These uncertainties are additional parameters that apply when you put a system into a quantum context such as a theory of quantum gravity," Bojowald said. "It is similar to the uncertainty relations in quantum physics, where there is complimentarity between the position of an object and its velocity -- if you measure one you cannot simultaneously measure the other." Similarly, Bojowald's study indicates that there is complementarity between the uncertainty factors for the volume of the universe before the Big Bounce and the universe after the Big Bounce. "For all practical purposes, the precise uncertainty factor for the volume of the previous universe never will be determined by a procedure of calculating backwards from conditions in our present universe, even with most accurate measurements we ever will be able to make," Bojowald explained. This discovery implies further limitations for discovering whether the matter in the universe before the Big Bang was dominated more strongly by quantum or classical properties.
"A problem with the earlier numerical model is you don't see so clearly what the free parameters really are and what their influence is," Bojowald said. "This mathematical model gives you an improved expression that contains all the free parameters and you can immediately see the influence of each one," he explained. "After the equations were solved, it was rather immediate to reach conclusions from the results."
Bojowald reached an additional conclusion after finding that at least one of the parameters of the previous universe did not survive its trip through the Big Bounce -- that successive universes likely will not be perfect replicas of each other. He said, "the eternal recurrence of absolutely identical universes would seem to be prevented by the apparent existence of an intrinsic cosmic forgetfulness."
What Was Before The Big Bang??
It's not known, there are many theories but also time as we know it is a property of our universe, it is not understood if "before" was even a thing without the universe since time and space are inseparably linked.
There's a theory that the big bang is the result of a singularity exploding outwards
As in, a point of infinite mass and energy
The density is infinite, but the mass is still finite in the singularity.
In other words, it contains the entire universe and the universe is finite.
i think its called the brane theory or something like that, something about these higher dimensional membranes collided causing the big bang. Has to do with string theory and a lot of other cosmological theoretical weirdness
What was to the North West of Thursday?
By which I mean 𧯯ore the big bang' may not be a sensical concept, as time may only exist within the context of the universe.
Our whole universe was in a hot, dense state then nearly 14 billion years ago expansion started.
That's as good an explanation as any!
The very idea of before the big bang (or "beginning" of the universe, etc) doesn't make much sense, as time is generally thought to not have existed prior to the universe existing.
Some scientists believe this universe was the creation of another universe collapsing.
There are thoughts about what happened before the big band but we can't actually know. There might have been just nothing. But then again seeking about time when there was nothing to change doesn't make a lot of sense.
Was it the Glen Miller orchestra?
But seriously, don't think anybody knows. Heck even the Big Bang still remains a theory to explain the creation of the universe, although there are many indicators that seem to hint it's a correct interpretation , it's not like everyone can go back in time to verify said theory (in before people go all metaphysical about time not existing and crazy inter-dimensional / quantum physics stuff gets added to the mix).
That said, I think Humanity has trouble imagining things that do not have a creation, a creator, a start and an end. People need to know when something started and how it ends because that's how our brains are wired to see our everyday reality (you are born , you age , you die, same with our plants, our planet and our reality). We're so used to this mode of thinking that the universe has to have a beginning and an end, but to me , it always made more sense to consider that at some point we have to accept that something was there in the first place. Not everything has to have a beginning or an end, and there's a certain amount of security in the concept of timelessness, of some things being because that's how the universe works and will always work like.
Kinda like Religion, many people find it convenient to think of a being that created everything, but to me that always opened the question of who created said god-like being if that's the case ? And if god created itself, always felt that it's an pushing the true questions one layer further (but who created god then?) and not solving any of them by saying "well said entity created himself".. But who created that someone, why or when ? This does not solve anything, it's just a cop out not to have to explain anything.
At the end of the day, either there was something from the start or there was nothing and suddenly there was something, but both theories are just as valid to me.
Still I tend to prefer theories that accept that there's something timeless and ever-existing in our universe, and most of the complexity we see and can't comprehend is just our minds unable to explain the rules of this complex system. Nothing is that complex, we're just too deep into said system to see the complexity and be able to comprehend it on the scale where everything would make sense.
Dumb question: The big bounce theory, how likely is it?
About the end of the universe there are a few theories going around including but not limited to:
I am asking the question in the title (The big bounce theory, how likely is it?) in order to get more information about this subject and get more points of view.
As you probably know, the big bounce says that the universe will expand and then collapse upon itself before a new big bang happens and it will expand again like the beating of a heart. I like the big bounce because it also answers the question what was before the big bang, an other universe.
I think that this could mean that the centre of our universe has a mother star which everything circles around, since the universe is still expanding. Once this star becomes a black hole then its gravity would be so strong it would devoir everything again making a new big bang event.
So what do you guys think? Is the big bounce probable or do you think our universe will have another outcome and am I making a major error in my reasoning?
1 Answer 1
Your argument is based upon the idea that all the matter in the universe was created at the moment of the Big Bang. If matter can be created from nothing at the moment of the Big Bang then it does seem reasonable that matter could disappear again, as you say.
The trouble is that there is no experimental or theoretical support for the idea that matter was created at the Big Bang. In fact the Big Bang theory is actually something of a misnomer because the theory specifically excludes the moment of the Big Bang itself. The theory (more precisely the FLRW metric) tells us the geometry of the universe for any time $t > 0$, but does not tell us what happened at $t = 0$. In fact strictly speaking the time $t = 0$ is not part of the universe - general relativity considers the universe to be everything except the moment of the Big Bang itself. We have no theory that tells us what happened at the moment of the Big Bang, so we have no theory that tells us what happened to all the matter in the universe at that moment.
So your argument is not a valid one. We do not know whether matter was created at the Big Bang, so you can't use that claim as evidence that matter can disappear again. This is why Googling has failed to find any support for the idea of disappearing matter.
The closest we have to a theory that tells us what happened at the moment of the Big Bang are speculative ideas from various theories of quantum gravity that suggest there never was a Big Bang but instead a Big Bounce. If (and it's a big if) there is anything to these ideas then we don't have to worry about matter appearing or disappearing. The matter was there before the Big Bounce, made it through the Big Bounce and was still there after the Big Bounce.
The banality of danger
In listening to these talks I was struck by how mundane the sources of these dangers were when it comes to day-to-day life. Unlike nuclear war or some lone terrorist building a super-virus (threats that Sir Martin Rees eloquently spoke of), when it comes to the climate crisis and an emerging surveillance culture, we are collectively doing it to ourselves through our own innocent individual actions. It's not like some alien threat has arrived and will use a mega-laser to drive the Earth's climate into a new and dangerous state. Nope, it's just us — flying around, using plastic bottles, and keeping our houses toasty in the winter. And it's not like soldiers in black body armor arrive at our doors and force us to install a listening device that tracks our activities. Nope, we willingly set them up on the kitchen counter because they are so dang convenient. These threats to our existence or to our freedoms are things that we are doing just by living our lives in the cultural systems we were born into. And it would take considerable effort to untangle ourselves from these systems.
So, what's next then? Are we simply doomed because we can't collectively figure out how to build and live with something different? I don't know. It's possible that we are doomed. But I did find hope in the talk given by the great (and my favorite) science fiction writer Kim Stanley Robinson. He pointed to how different eras have different "structures of feeling," which is the cognitive and emotional background of an age. Robinson looked at some positive changes that emerged in the wake of the COVID pandemic, including a renewed sense that most of us recognize that we're all in this together. Perhaps, he said, the structure of feeling in our own age is about to change.