This article first appeared in the Christian Research Journal, volume 42, number 3/4 (2019). For further information or to subscribe to the Christian Research Journal please click here.
SYNOPSIS
Over the last 100 years, scientists have made remarkable discoveries that seem to indicate our universe came into existence about 14 billion years ago. Additionally, theoretical calculations predict that the history of our universe includes an actual beginning. Yet we do not have a confirmed scientific theory that describes the very moment of the origin of the universe, so there is significant speculation about what may have actually occurred, whether an absolute beginning is necessary, and what may have existed before our universe. The persistent message from scientists is that we just don’t know whether or not the universe had a beginning and, even if it did, that gives us no information about whether or not there is a transcendent creator. However, in contrast to speculative ideas, the science that is known to be true not only provides abundant evidence that the universe had a beginning, but also that the origin of the universe gives support for the biblical record and the biblical God.
In 1929 the astrophysicist Edwin Hubble published a paper that fundamentally changed our understanding of the universe.1 Hubble showed that galaxies outside the Milky Way were moving away from us, and that the farther a galaxy was from us, the faster it was moving away. The linear relationship between these two quantities, distance and speed, suggested that the universe was expanding at a constant rate. If we extrapolate that motion backwards into the past, the entire visible universe was at one time concentrated nearly into a single point. The implications of this discovery were immediately evident: a universe that is expanding now must have started to expand. It must have had a beginning.
The idea that the universe had a beginning was not readily accepted by scientists at that time, and it is still not appealing to many. If the universe had a beginning, it may have had a beginner. In fact, the term “big bang” was first used by physicist Sir Fred Hoyle as a pejorative description, apparently trying to discourage the acceptance of this hypothetical beginning. Yet all physical observations and theories based on known physics stubbornly continue to strengthen the case for a cosmic origin.
THE COSMIC MICROWAVE BACKGROUND RADIATION
Perhaps the most comprehensive and compelling evidence for the big bang comes from the cosmic microwave background (CMB) radiation. If we extrapolate the current expansion backward in time using the known laws of physics we come to a time, billions of years ago, when the entire visible universe was extremely small and hot. Although the universe has expanded and cooled since, we should still be able to detect traces of that primordial heat.
In 1948 Ralph Alpher and Robert Herman published a paper in which they calculated that if the universe started in a hot dense state, then today it should have a temperature slightly above absolute zero (–460 °F) that is fairly uniform throughout its volume, and visible as microwave radiation.2 This radiation, the CMB, was discovered accidently by Arno Penzias and Robert Wilson in 1964. Subsequent measurements by balloon-borne instruments and by satellites COBE (Cosmic Background Explorer launched in 1989), WMAP (Wilson Microwave Anisotropy Probe launched in 2001), and Planck (launched in 2009) have provided better resolution and detailed information about the nature, or spectrum, of the CMB that agree with the big bang cosmological model to about one part in ten thousand, a remarkable achievement for any scientific theory.3
ONE TERM: TWO DEFINITIONS
In current usage the term “big bang” is somewhat ill-defined with at least two meanings. One meaning, as I am using it in this article, refers to the moment when our universe began, which was its original meaning as conceived by Hoyle. The other meaning refers to sometime shortly after the beginning when we have considerable confidence in our understanding of the physical laws that govern the universe, from roughly 10-32 to 10-12 seconds after the origin. Headlines that proclaim things like “The Big Bang Wasn’t the Beginning after All”4 are using this second meaning and defining the big bang as the moment shortly after the origin when the known laws of physics are operational. Almost all scientists agree that we understand the general 14-billion-year history of the universe from a fraction of a second after its origin until now, but that we don’t have any definite observational evidence, and few unequivocal theoretical calculations, about what happened before that.
THEORETICAL PHYSICS AND THE BGV THEOREM
While observational evidence has driven the development of the big bang model, theoretical ideas have contributed to our understanding of what may have occurred at the moment of its inception. Even before Hubble discovered the expanding universe, Albert Einstein had published his general theory of relativity, which is the best current model of how gravity works.5 Einstein’s original equations suggested that the spatial dimensions of the universe could not be static but should be either expanding or contracting. Because there was no evidence for such universal motion, Einstein added a term to his equations to cancel out this effect. Hubble’s discovery showed that this added term was unnecessary. In the late 1960s and early 1970s Stephen Hawking and other collaborators published papers that expanded Einstein’s equations to include time and concluded that the general theory of relativity implied that both space and time seemed to have an actual beginning.6 Their equations indicated that the entire universe — its energy, space, and time — was originally compressed into a singularity of infinite density. In other words, the mathematical equations of the general theory of relativity predict that the big bang was the origin of the space, time, matter, and energy of our universe. It was not an “explosion” from existing material but a beginning of the universe, completely compatible with an ex nihilo creation — creation out of nothing.
The theoretical confirmation of a cosmic origin was further strengthened in 2003 when Arvind Borde, Alan Guth, and Alexander Vilenkin published a paper that showed basically that any universe that is expanding on average cannot have a history that can be extended forever into the past.7 Any such universe, which ours seems to be, must have had a beginning. Their idea, the “BGV theorem,” is extremely general. It does not depend on a specific model of gravity or on the application of general relativity. It holds for oscillating universes (ones that expand and collapse repeatedly) or a universe that is part of a multi-verse (many other universes). In Vilenkin’s words, “With the proof now in place, cosmologists can no longer hide behind the possibility of a past-eternal universe. There is no escape: they have to face the problem of a cosmic beginning.”8
BIG BANG PROBLEMS AND COSMIC INFLATION
As our understanding of the big bang became more sophisticated and the CMB was measured more precisely, a few “problems” developed with the original big bang model. At least three of the supposed problems can be solved with a proposal called cosmic inflation.
The horizon problem occurs because the CMB temperature is almost the same throughout the entire visible universe. However, the universe is so large that light has not had enough time to have traveled between the most distant points, and consequently the different parts of the universe should not have had any interaction with each other. Therefore, it seems surprising that the whole universe has nearly the same temperature, since some locations could have never been in contact with other locations to allow their temperatures to equilibrate.
The flatness problem has to do with the geometry of space in our universe. It is most probable that space has some curvature, like the surface of a sphere, but instead it is “flat” like a piece of paper, which is highly unlikely.
The monopole problem arises because any attempt to unify three of the four fundamental forces in nature (electromagnetic force, strong force, and weak force) predicts that the universe should contain monopole particles with only a north or south magnetic pole. But no such particles have ever been discovered.
It is worth noting at this point that the first two “problems” are only problems because naturalistic approaches do not easily explain an improbable universe that is flat with a constant temperature. If there is an intervening designer, then these are not necessarily problems at all.
All three problems can be solved with cosmic inflation, which proposes that during the first 10-32 seconds after the big bang, the universe went through a period in which its space dimensions expanded exponentially, doubling in size at least 90 times. With inflation, all the universe we see now was at one time causally connected, so the horizon problem is solved. Inflation forces the geometry of the universe to be nearly flat, and it spreads monopoles so far apart that we may never find one nearby. Currently, there is no conclusive evidence that inflation occurred, but it is embraced by most scientists, and observations are consistent with inflationary models.
The most popular theory of inflation, originally proposed by Alan Guth but further developed by a number of physicists, has a bearing on the origin of the universe.9 In certain versions of this theory, inflation is somewhat like bubbles in a carbonated beverage with each bubble being a different universe. Different universes can grow to different sizes and take different forms, but once the process of inflation begins, it will continue on forever, creating a potentially infinite number of “bubble” universes. Thus, our universe would be simply one in a sequence of universes that will continue on forever in some form, a process called “eternal inflation.”
SCIENTIFIC KNOWLEDGE
The observations and calculations that have led to our understanding of the standard cosmological model, including the big bang, elicit the question of whether or not science has proven that the universe had a beginning. The answer to that question requires an understanding of the nature of scientific knowledge. In the strictest sense, science cannot prove anything. Even ideas that we think are universally true would require only one confirmed violation to be disproven. For instance, Einstein’s special theory of relativity, which describes the motion of objects moving at velocities near the speed of light, has never been shown to have any violation and is expected to apply to all situations. In some sense, scientists “know” that it is true. Yet, if any experiment showed even one instance in which the theory did not hold, then we would conclude that it is not absolutely true but was a very good approximation to a more overarching theory. Rather than portray ideas as known or proven in science, it is more accurate to claim that scientific theories have various levels of confidence and applicability.
DID THE UNIVERSE HAVE A BEGINNING?
Because there are no proofs in science, perhaps the best way to phrase the question of what science tells us about the origin of the universe might be something such as, “Does modern cosmology really imply that the universe had a beginning?” The short answer is “yes.” The scientific evidence for the beginning is very strong. All observations indicate that the universe had a beginning, and no observations contradict this conclusion. In addition, all of the theoretical ideas that are based on confirmed physics predict that the universe had a beginning. From what we do know it might seem that the question of a cosmic beginning has been scientifically settled and the door on any dissent has been closed. But the things we don’t know leave the door open a crack.
QUANTUM GRAVITY
Two of the most successful theories in all of science are the general theory of relativity (which describes gravity) and quantum theory (which describes the universe at very small distances, the size of atoms and smaller). However, scientists have been unable to develop a cohesive theory that combines general relativity with quantum theory, meaning we don’t have a reliable theory of how gravity works at extremely small distances. But before inflation, when the universe was much less than 10-35 seconds old and far smaller, it was certainly governed by laws of physics that describe gravity at tiny distances. Since we don’t have such a theory, we don’t know what principles operated before then or how the universe behaved. Consequently, when asked whether or not the universe had a beginning, most scientists will reply that we just don’t know. Although this answer is technically always correct given the nature of scientific knowledge as described above, it avoids the legitimate scientific question, “What are the likely conclusions that can be drawn about the origin of the universe given all the known observations and calculations?” Or as stated above, “Does modern scientific cosmology imply the universe had a beginning?”
WHY IS THERE SOMETHING RATHER THAN NOTHING?
Because we don’t have a theory of quantum gravity that might describe the earliest moments of the universe, scientists offer many speculative alternatives to our single universe having an actual beginning. A short, noncomprehensive list of proposed alternatives includes:
- Our universe did not have an actual beginning, as suggested by Stephen Hawking’s imaginary time in A Brief History of Time.10
- The beginning of our universe is just one beginning in a sequence of many universes having many beginnings, as predicted by eternal inflation.
- The boundary of our universe that looks like a beginning is not a true beginning, as proposed by Anthony Aguirre and Steven Gratton.11
- The beginning of our universe is a purely natural event, possibly with no cause whatsoever, as described by Lawrence Krauss in A Universe from Nothing.12
- The universe necessarily exists and requires no further explanation, as suggested by Sean Carrol.13
All these propositions have some common attributes. First, they are not based on any actual observations. Second, they all require some new physical laws of nature that have not been discovered. Third, these new laws of physics would have to displace the conclusions of known laws of physics, including classical general relativity and the BGV theorem. Finally, all proposals (possibly with the exception of proposal 5) would still have an event in which our universe did come into existence about 14 billion years ago.
Closer examination reveals that all proposals still require a cosmic beginning or have extreme philosophical problems. Each item below gives a rebuttal to the corresponding numbered proposal above:
- Hawking’s imaginary time removes the singularity at the origin of the universe but still has a point in space-time that looks just like a big bang beginning.
- The BGV theorem applies to inflation, so some time in the past was the beginning of the process of eternal inflation. Thermodynamic considerations would imply the origin is not too far in the past.
- The boundary does require an actual beginning of our universe, though other universes could be spawned at the same time.
- Philosophers and scientists agree that Krauss improperly uses the term “nothing” and that his proposal requires a previous existing entity.
- The universe as a brute fact violates all laws of causality and can be shown to be inconsistent with philosophical naturalism, thus requiring some transcendent cause.
These very brief rebuttals are not meant to be exhaustive or comprehensive, but simply illustrate the kinds of problems inherent in solutions that try to avoid a beginning of the universe. It is impossible to develop any complete list of alternatives to the big bang or rebuttals to those proposals since new speculations are consistently being developed.
Quantum Gravity and the BGV Theorem
Although the BGV theorem requires that any universe expanding on average had a beginning, some scientists will argue that the BGV theorem is based on classical space-time and is likely not applicable in the realm of quantum gravity. Such a criticism may seem compelling because it seems to contrast a “classical” theory, which may be incorrect at small distances, with a “quantum” theory, which is applicable at all distances. But that is not the case. Classical space-time is not the same as a classical theory, and quantum space-time is not necessarily the same as a quantum theory of gravity. Classical space-time may indeed extend to infinitesimally small distances. It basically means only that time has a directionality, and causality can be defined. So any universe expanding on average governed by any theory of quantum gravity that retains a direction of time is still constrained by the BGV theorem. An appeal to quantum gravity to invalidate the BGV theorem is not only an appeal to ignorance but also requires the extraordinarily counter-intuitive idea that the correct theory of quantum gravity will ultimately have no direction of time and no causality. Even then, any definitive conclusions about the origin of the universe would depend on the exact nature of the confirmed theory, and it is likely the conclusions of the BGV theorem would remain valid.
A “Natural” Beginning
Although all the scientific evidence supports a creation of our universe ex nihilo, and that seems to be the best understanding of the biblical text, suppose future discoveries conclusively demonstrated that there was some pre-existing natural entity that spawned this universe. Would that change the answer to the question of whether or not this universe had a beginning and avoid the implication of a transcendent creator? I would argue that even in such a case the scientific observations would support the biblical record and the biblical God for a number of reasons. First, the Bible states, “In the beginning God created the heavens and the earth” (Gen. 1:1 NIV), which describes the origin of only this universe. Second, a biblical study of how God works in nature reveals that He often acts through natural law. He actively feeds the lions, causes the sun to rise, clothes the lilies, and countless other acts through His laws of nature. If He created this universe through some “natural law” mechanism, then He would still be involved, this universe would still have a beginning, and the cause of this universe would still have to exist apart from the universe. Third, the known laws of physics, like the BGV theorem and thermodynamic considerations, suggest no previous natural cause or, at most, a very short chain of causes with the first having an actual beginning in the recent past. Consequently, the case for a transcendent God who brought the created order into existence without a material cause at some point in the finite past remains just as compelling.
THE SCIENTIFIC IMPLICATION
Science is based on observations, experiments, and predictive calculations. Scientific knowledge advances through developments within these foundational principles. Currently, all scientific data validate the same conclusion, that our universe had a beginning. Although we don’t know what happened in the first 10-32 seconds of the universe, all that we do know clearly points to an actual beginning. Any cause of our universe must then, logically, be separate from the universe itself; a transcendent cause consistent with God as described in the Bible.
Michael G. Strauss (BS, Biola University; PhD, University of California, Los Angeles) is a David Ross Boyd Professor of physics at the University of Oklahoma in Norman. He conducts research in experimental particle physics at CERN in Geneva, Switzerland. He is author of the book The Creator Revealed: A Physicist Examines the Big Bang and the Bible (Westbow Press, 2018) and one of the general editors of the Dictionary of Christianity and Science (Zondervan Academic, 2017).
NOTES
- Edwin Hubble, “A Relation Between Distance and Radial Velocity among Extra-galactic Nebulae,” Proceedings of the National Academy of Sciences of the United States of America 15 (1929): 168–173.
- Ralph Alpher and Robert Herman, “On the Relative Abundance of the Elements,” Physical Review 74 (1948): 1737–1742.
- Hinshaw, et al., “Nine-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Parameter Results,” The Astrophysical Journal Supplement 208 (2013): 19.
- Ethan Siegel, “The Big Bang Wasn’t the Beginning, after All,” Forbes, September 21, 2017, https://www.forbes.com/sites/startswithabang/2017/09/21/the-big-bang-wasnt-thebeginning-after-all/#7e0658a155df.
- Albert Einstein, “Die Feldgleichungen der Gravitation,” Sitzungsberichte der Preussischen Akademie der Wissenschaften zu Berlin (1915): 844–847.
- Stephen W. Hawking and George F. R. Ellis, “The Cosmic Black-Body Radiation and the Existence of Singularities in our Universe,” The Astrophysical Journal 152 (1968): 25–36; Stephen W. Hawking and Roger Penrose, “The Singularities of Gravitational Collapse and Cosmology,” Proceedings of the Royal Society of London, series A, 314 (1970): 529–548.
- Arvind Borde, Alan Guth, and Alexander Vilenkin, “Inflationary Spacetimes Are Incomplete in Past Directions,” Physical Review Letters 90 (2003): 1–4.
- Alex Vilenkin, Many Worlds in One: The Search for Other Universes (New York: Hill and Wang, 2006), 176.
- Alan H. Guth, “Inflationary Universe: A Possible Solution to the Horizon and Flatness Problems,” Physical Review D 23 (1981): 347–356; A. Albrecht and P. J. Steinhardt, “Cosmology for Grand Unified Theories with Radiatively Induced Symmetry Breaking,” Physical Review Letters 48 (1982): 1220–1223; Alexander Vilenkin, “Birth of Inflationary Universes,” Physical Review D 27 (1983): 2848–2855; Alan H. Guth, “Eternal Inflation and Its Implications,” Journal of Physics A 40 (2007): 6811–6826.
- Stephen Hawking, A Brief History of Time: From the Big Bang to Black Holes (New York: Bantam Dell Publishing, 1988).
- Anthony Aguirre and Steven Gratton, “Inflation without a Beginning, a Null Boundary Proposal,” Physical Review D 67 (2003): 083515.
- Lawrence Krauss, A Universe from Nothing: Why There Is Something Rather Than Nothing (New York: Free Press, 2012).
- Sean M. Carroll, “Why Is There Something, Rather Than Nothing?” arXiv:1802.02231 [physics.hist-ph], Cornell University, June 4, 2018, to be published in the Routledge Companion to the Philosophy of Physics (Routledge), eds. E. Knox and A. Wilson.
