IBRI Research Report #15 (1982)
A CRITICAL EXAMINATION OF MODERN COSMOLOGICAL THEORIES
Robert C. Newman
Biblical Theological Seminary
Copyright © 1982 by Robert C. Newman. All rights reserved.
|Although the author is in agreement with the doctrinal statement of IBRI, it does not follow that all of the viewpoints espoused in this paper represent official positions of IBRI. Since one of the purposes of the IBRI report series is to serve as a preprint forum, it is possible that the author has revised some aspects of this work since it was first written.|
Cosmology is the study of the known parts of the universe in an attempt to describe the universe as a whole. It is the interpretation of that information presently reaching the earth with a view to reconstructing the entire history of the cosmos. With limitations such as these, we should not be surprised that cosmology is still more speculation than it is science, and that a great variety of cosmological models are proposed and defended.
Like physicist Hannes Alfven, we may wish to throw up our hands and dismiss cosmology as a waste of time.1 Yet the questions it deals with are too important to be safely ignored. The Bible warns us that the universe is created and that its Creator will one day call us to account for our every thought and action (Rom 2:15-16; Rev 20:11-15). However unlikely we might think it that the Bible is really a message from God or that Christianity is true, the stakes are so high if we are mistaken that it would be foolish for us to live like the universe is eternal without carefully examining whatever data may bear on the subject.2
Not only are questions of cosmology personally important for each of us (whether we realize it or not), but the scientific material available to answer these questions is more extensive today than ever before. With the development of ever-larger optical telescopes, or radio telescopes since World War 2, and most recently of artificial satellites which make observations above our obscuring atmosphere, we now have enormous amounts of new data. Earthbound work in physics has given us greatly increased understanding of the atom, its nucleus and elementary particles, and of the gravitational, atomic, and nuclear forces at work in the universe. Therefore we are responsible to press on in this "sore travail" that God has given us, "to seek and search out by wisdom concerning all things that are done under heaven" (Eccl 1:13).
In this paper, we shall sketch the scientific data relevant to cosmology, including such items as the nature of stars and their distances from us, galaxies and their redshifts, Olber's paradox, cosmic distance scales, quasars, and the so-called three-degree blackbody radiation. At convenient points in this discussion, we shall examine various cosmological models, some proposed by secular scientists, others by various Bible-believers. In the end, we shall summarize our findings and propose a best model on the basis of present scientific knowledge.
The Nature of Stars
Although astronomers are interested in planets, asteroids and comets as well, cosmologists tend to confine their study to stars and galaxies, since these alone have been seen beyond our solar system.3 Let us first look at stars.
What is a star? We have one nearby -- the sun -- about 93 million miles (or eight light-minutes)4 away from us. The next nearest is about four light-years away, over a quarter of a million times further. Our sun is a huge ball of gas, mostly hydrogen, held together by its own gravity. The temperature at its visible "surface" is several thousand degrees. As we calculate the temperature inward, it rises to about ten million degrees at the center, so that the sun remains a gas all the way through in spite of enormous densities deep within. At such high central temperatures, hydrogen undergoes a nuclear reaction, converting itself to helium with the release of enormous amounts of energy. This energy, equivalent to the explosion of about two-billion 50-megaton hydrogen bombs per second,5 provides all our sunlight and keeps the sun from collapsing under the force of its own gravity. A mass of hydrogen equal to that of the sun should be able to keep burning by this reaction for perhaps ten billion years.
That, in brief is what the sun is like. Why do we believe the sun is a star, or equivalently, that the stars are suns? There are several reasons. First of all, we can measure distances to about a thousand of the nearest stars by a rather direct method of triangulation called parallax. This method is most easily illustrated by holding your finger up at arm's length and looking at it first with one eye and then with the other. Your finger appears to jump back and forth against its background. In astronomy, your finger corresponds to a nearby star; the background to the more distant stars. Your eyes are photos taken six months apart at opposite ends of the earth's orbit -- about 186 million miles apart instead of two inches. Measuring the amount of jump for each star, we find that the nearest stars are about four light-years (25 trillion miles) away. For stars beyond about 100 light-years, the jump gets too small to measure. Only about a thousand of the billions of stars visible in our telescopes show measurable jumps.
What does this have to do with whether the stars are suns? Well, when we allow for the geometrical dimming of light due to distance, we find that the brightness of our sun is the same as that for stars of the same color. Bluer stars tend to be brighter; redder ones dimmer. We can even make a graph, plotting star brightness opposite star color, and show that most of these stars lie near a single line (called "the main sequence") and that our sun lies on this line, too.
A second argument that stars are suns comes by measuring their masses. We can do this whenever stars occur in pairs or groups (called binary or multiple stars) rotating around one another. If we know the size of the orbit and the time it takes the stars to circle each other, we can immediately compute the sum of their masses. For main sequence stars, those with the same color as our sun have the same mass; bluer stars are heavier, redder ones are lighter.
In these and many other ways, stars show themselves to be the same kind of object as our sun. Of course, stars differ considerably among themselves: some are 100 times heavier than our sun, some 100 times lighter. Some have surface temperatures twice as cool; others, ten times hotter. Some expend their energy a million times faster; others a million times slower. However, there does appear to be a minimum size for stars. Observations agree with calculations that if an object is less than about 1% of the sun's mass, the central temperature will not be high enough to have a nuclear reaction, and the object will be a large planet like Jupiter rather than a star.
Camping's Physically Small Universe
At this point we are ready to consider the proposal of engineer and radio Bible teacher Harold Camping,6 that the whole universe is really very small, only a few light-years across. Camping argues that the parallax method described above merely shows us that the thousand nearest stars are closer than the background stars, but it doesn't tell us how far away these background stars are. All distance measurements used on the background stars, he says, are unreliable, being based on false assumptions. Instead, these stars lie in a thin spherical shell only a short distance further away.
This view is mistaken, as can be shown by several simple arguments based upon proportions, each of which is no less reliable than the parallax method which Camping accepts. First, we can measure the motion of stars toward or away from us by a shift in the frequency of light coming from them, using a technique like that of police radar for catching speeders. For those pairs of binary stars that are far enough apart to appear as separate stars in our telescopes, we measure the angular size of their orbits and the speed at which the two stars move around each other. If they are only a few light-years away, as Camping claims, then the physical size of the orbits must be relatively small, and the stars should complete a roundtrip in just a few days. In fact, however, many such stars take years to make a circuit, showing that those stars are actually many hundreds of light-years away.
Second, according to Camping's view, the dimmer main sequence stars must appear to be dim because they are very small rather than because they are very far away. For the billions of very dim stars we observe in large telescopes, most of these would have to be so small that gravity could not hold them together.
Third, these dimmer stars often form clusters. If we make a separate graph for each cluster, plotting star brightness opposite star color, a pattern is obtained which is similar to that of the thousand nearby stars. Each such graph has a main sequence line. If we assume that the main sequence in each cluster has the same actual brightness for each color as does the main sequence in our nearby stars, then these clusters are much further away from us -- some a hundred light-years, some a thousand, some even further. These assumption made here is very reasonable, since computer calculations of star structure show that stars on the main sequence are merely those which get their energy by turning hydrogen into helium, in contrast to (say) red giant stars, which have used up all their hydrogen, and are now turning helium into carbon, nitrogen and oxygen. Thus the view that the universe is much larger than a few light-years across is able to explain the energy source of stars in clusters by the same mechanism that explains the energy source of the sun and nearby stars.
Such examples could be multiplied easily. They show us that the universe is really much bigger than the distance to the nearest stars.
As we look further out into space, we see that most stars occur in clusters of hundreds or thousands of stars. These clusters, together with much gas and dust, form far larger collections of stars we call galaxies. The galaxy in which we are located is called the Milky Way, since its more distant stars form a "white road" across the sky to which the ancient Greeks gave this name. Our sun and the nearby stars are also a part of this galaxy, though they seem separate to us because we are among them. This is like the view we might have in a large city, where nearby lights are distinct from the glow of the more distant parts of the city.
Our galaxy is thought to have 100 to 200 billion stars. It is shaped like a spiral as viewed from above, or like a pair of marching-band cymbals placed face-to-face. The whole galaxy is some 100,000 light-years across, and we are about two-thirds of the way out from the center. Not far beyond our galaxy are two much smaller irregularly-shaped galaxies which we call the Magellanic Clouds since they were discovered (for Europeans) by Ferdinand Magellan on his voyage around the world. They cannot be seen from places as far north as the US. The nearest galaxy larger than ours is the Andromeda galaxy, containing some 200 to 300 billion stars and located about two million light-years away. Some galaxies are spirals, like the Milky Way and Andromeda. Some are ellipticals, like Andromeda's small companions. Others are irregulars, like the Magellanic clouds. The smaller galaxies have hundreds of millions of stars, the larger ones hundreds of billions.
How do we know the distances to other galaxies? Obviously not by parallax, since this method only works for the thousand or so nearest stars, all well within our own galaxy. The answer is that astronomers have developed a number of longer-range techniques for measuring distances. Each longer-range method is calibrated by using a technique that is good for shorter distances and which overlaps the range of the other. Techniques good over the same range are also checked against one another.
What are these distance-measuring techniques? Most of them depend on some method of calculating the actual or absolute brightness of a star, star cluster or galaxy. Then the apparent brightness of the object is observed. Since apparent brightness decreases with the square of the distance from object to observer, the distance of the object can then be calculated. We have already looked at one such method for determining absolute brightness main sequence stars of the same color have the same brightness. Another method depends on the fact that certain types of variable stars also have a definite average brightness which is related to the rate at which the star varies. Main sequence stars and these variable stars are used to measure distances within our galaxy and out to several nearby galaxies, to a distance of a few million light-years. In nearby galaxies, we notice that the brightest stars in a galaxy and the brightest (globular) clusters tend to have a fixed brightness, by which distances can be measured out to a hundred million light-years. Beyond this distance, measurements are less certain, though it appears that the brightest galaxies in large galaxy-clusters also have a fixed brightness. This gives very rough distance measurements out to the most distant known galaxies, over a billion light-years away.
Moon and Spencer's Optically Small Universe
Two secular scientists, Parry Moon and Domina Spencer,7 have proposed that certain phenomena of binary stars usually explained by Einstein's theory of relativity could be explained without using relativity if we assume that light travels in circles of radius five light-years rather than in straight lines. In such a cosmology, the universe may be arbitrarily large in actuality, but an observer could never see objects more than ten light-years away, since light from more distant sources would curve back on itself before reaching us. Yet though there exist only a dozen or so stars within ten light-years, these might be supposed to appear to us as billions of stars as we see their light on its first, second, third, or even millionth circuit around the heavens.
This suggestion seems to have attracted little interest in secular circles, but a number of young-earth creationists have spoken favorably of it.8 These creationists see such a model as a possible explanation for how light from apparently distant objects could reach us in just a few years, thereby avoiding the problem of having God create light already on its way to us for objects over 10,000 light-years away. Unfortunately, the cosmology of Moon and Spencer will not solve this problem, and it is hardly likely to be the actual state of affairs in any case.
In the first place, this model does not solve the problem of light travel-time. Even though the apparently brightest stars might be those we are seeing directly, and the dimmer ones might be light from the same stars which has made many more trips around the "universe," this dimmer light must still have travelled a long way and taken a long time to do it. Only the light from the first, direct images of the stars would reach us in less than fifteen years. The second-image light would have had to make an additional circuit, arriving about thirty years later (circumference of circle with diameter ten light-years). Light which by dimness and other distance-measuring techniques appears to have come from more than 10,000 light-years away would actually have made several hundred circuits and taken over 10,000 years to do so. It therefore does not appear that the optically-small universe of Moon and Spencer is any help for young-earth creationists.
Nor is the model at all likely to be true. Since the radius of curvature for light rays in this model is five light-years, we would see nothing that is actually further away than ten light-years. This would mean that our sky has only a handful of real stars and all the rest of the star images are multiple "reflections" of these. This would be very much like looking into one of those "wrap-around" mirrors sometimes found in clothing stores or amusement parks, in which we see many images of ourselves. It should only take a few minutes' study of astronomical photographs to convince us that we are not merely looking a multiple reflections. The images of globular clusters and galaxies, for instance, are too coherent with centers, rotational motion, and such to be the multiple images of only a dozen stars! Then, too, there are far more than a dozen different star colors, sizes and densities which we observe.
Since the 1920s we have known that (except for a few galaxies in our local group) the light coming to us from all the galaxies is redshifted. This means that the dark lines in the spectrum of each galaxy (caused by the various chemical elements in the cooler outer atmospheres of each star absorbing the light passing through) are located at longer wavelengths (corresponding to redder light) than they are for absorption by the same elements in a laboratory on earth.
Not only is the light redshifted, but the amount of shift is larger for more distant galaxies, increasing in an approximately linear way with distance. There are only three known mechanisms that redden light: (1) scattering by dust and gas, (2) gravity-reddening, and (3) motion-reddening. The first of these is what causes the sun to look red near sunset when its light passes through many more miles of atmosphere to reach us than it does when overhead. For galaxies, though, this reddening would be due to gas and dust in outer space between us and the galaxies. This kind of reddening would increase with distance like the redshift does, but it wouldn't shift the spectral lines. Therefore, this cannot be the proper explanation.
Gravity-reddening is due to the energy lost by light as it fights its way out of a strong gravitational field. It does shift spectral lines toward the red, but there is no reason why it should produce more reddening for more distant galaxies. This explanation, too, is inadequate to explain the galactic redshifts.
Motion-reddening is a shift in light-frequency due to the movement of the light source and observer away from one another. More commonly known as the Doppler shift, it also allows for blueshifts when source and observer are approaching one another. Most of us have observed the Doppler shift of sound waves in noticing the change in pitch of a train whistle, auto engine, or siren when the vehicle passes us. The tone is higher-pitched as the vehicle approaches and suddenly drops as it passes and begins to move away. For light waves, it is color, not pitch, which we observe, and the color seems bluer for approaching objects and redder for receding ones. The effect for light is not noticeable at ordinary speeds without special equipment, and we do not commonly see objects travelling at an appreciable fraction of the speed of light. This explanation will fit the observed galactic redshifts if we assume that all galaxies except a few in our local group are moving away from us. This assumption, known as the expansion of the universe, is generally accepted by cosmologists today.
A Static "Tired-Light" Universe
Some cosmologists, however, prefer to postulate some unknown mechanism to produce the galactic redshifts rather than to accept the strange idea that all the galaxies are moving apart. Cosmologies which deny an expanding universe are called "static" universes (not to be confused with the "steady-state" universe which we will discuss later). The various mechanisms proposed for reddening are usually called "tired-light" theories.
French physicist Jean-Pierre Vigier,9 for instance, proposes that an otherwise unknown lightweight elementary particle exists which scatters light in such a way as to redshift the spectral lines in proportion to the distance the light has travelled. Such a cosmology cannot be ruled out under present knowledge as far as I know. However, scientists are reluctant to postulate unknown forces or particles without some more definite evidence. Such a large static universe created at some finite time in the past could fit the observed data.
If, however, one proposes a static universe which is uncreated and therefore eternal, several other problems arise. Since gravity is only an attractive force, such a universe would not remain static unless another unknown force is postulated to balance gravity. This is what Einstein did by adding his "cosmological constant" to his equations. He was not willing at the time to have a universe with a beginning.10
Another problem for a static, eternal universe is that stars have a fixed amount of hydrogen fuel and a substantial rate at which they burn this fuel. Therefore no star burns forever. Since stars are still burning today, proponents of an eternal static universe must postulate some unknown mechanisms to "recycle" fuel. Such a process would presumably use considerable energy itself, or violate the principle of entropy by which energy tends to disperse.
Eternal static universes of infinite size are also troubled by Olber's paradox. Named for a 19th century astronomer, this paradox arises from the obvious fact that the sky is dark at night. An eternal universe filled with stars should have a bright sky. Let me explain. The brightness of a light diminishes as the square of our distance from its source. If (in our imagination) we divide up the universe into spherical shells of equal thicknesses centered on ourselves, each shell increases in volume as the square of the distance from us, exactly canceling the diminishing of the light from each star in the shell. Therefore, each shell having the same density of stars will give us the same amount of light no matter how far away it is!
For an infinite universe, the sky should be infinitely bright, or allowing for stars to block the light coming from stars behind them the sky should be as bright as the surface of an average star! Obviously this is not the case. The paradox can only be avoided if one of the following is true: (1) the universe is finite in size, so that there is no light provided by shells beyond a certain distance; (2) the universe is finite in age, so that no light has yet reached us from shells beyond a certain distance; (3) the universe is expanding in such a way that shells beyond a certain distance are travelling away from us faster than the speed of light, and their light will never reach us; or (4) the universe is organized in a spatial hierarchy11 such that more distant shells have less and less stars in just such a way that the total sky appears dark compared with daytime.
Only the last of these four cases permits an infinitely large and infinitely old static universe, and this is such a peculiar special case that few would be willing to defend it. Since it still fails the problem of gravity and fuel that trouble other static cosmologies, we conclude that a static universe, eternal or not, really doesn't fit the known scientific data without very specialized assumptions about the existence of unknown laws.
A Young "Created Light" Universe
Many young-earth creationists believe that our universe is very large (whether static or expanding) but very young, no more than about 10,000 years old. Since most of the objects visible in our larger telescopes give every indication of being more than 10,000 light-years away (which distance is still inside our galaxy), many proponents of this view claim that the light from these distant objects was created on its way to us and never actually left the objects which the light represents.12
Such a view is defended on the grounds that God created objects with apparent age that Adam, for instance, looked full-grown, say 25 years old, only a moment after he was created; that newly-created trees had growth rings in them; that the wine Jesus created at Cana tasted like it had been grown on vines and aged. There is certainly some merit to the idea of a fictitious apparent age for objects brought into existence suddenly. However, not being present, we can only speculate on whether or not such an apparent age would be indistinguishable from actual age. Would newly-created trees really have growth rings? Would Adam have a navel (say), even though he was never born? Would he have toughened or baby-soft skin? We don't know.
But this view, when applied to cosmology, must take an additional and substantial step from apparent age to fictitious history. Let me explain. When we look out into space (with or without a telescope) we are effectively looking back into history because light takes time to travel. Looking at the sun, we see events that happened there about eight minutes ago, since we are about eight light-minutes away. When we observe the star alpha Centauri (about four light-years away), we see what was happening there four years ago. Similarly, for more distant stars, we see their radiation, flares, variation, rotation, position, etc. the events occurring on them when light left these stars, whether 10, 100 or 1000 years ago. But according to the theory of a young "created light" universe, when we reach (say) a distance of ten thousand light-years, we suddenly shift from real history to fictitious history without any seam (say, some sort of flash or discontinuity) to indicate that anything unusual happened. Thus the phenomena we see in the Andromeda galaxy, for example, represent merely the galactic rotation, stellar positions, supernova events (stellar explosions), expanding gas clouds, etc., that would have happened had the galaxy existed two million years ago. Yet these events didn't actually happen because none of these things existed. Such a view bristles with both scientific and theological problems far more severe (it seems to me) than the suggestion that the Bible does not narrate a recent creation.
Another way to have a large, young universe which is less troublesome theologically is to assume that the speed of light was very high or infinite at creation, so that light from all the distant reaches of the universe reached the earth immediately or soon after creation; thereafter the speed of light decreased to its present value. This proposal was first made by Barry Setterfield, and has been entertained with favor by others.13 Unless the speed of light immediately dropped to its present value, it should (on this proposal) be higher as we look back into the past.
There is no observational evidence for this from sources at astronomical distances. Some important constants occurring in spectroscopy involve the speed of light (e.g., the fine-structure constant, and the proton magneton related to hyperfine structure).14 If this proposal were valid, we should be able to detect it by observing the fine and hyperfine structure in the spectra of stars and interstellar gas. This would be difficult at optical wavelengths because the detail gets lost in the motions of the gas. But at radio wavelengths the radiation is often due to transitions between fine and hyperfine energy levels. Thus the so-called 21-centimeter spectral line of hydrogen is a hyperfine transition, but it gives no evidence for a change in the speed of light as far out as we can detect it (several million light-years so far).15
It is true that Barry Setterfield has argued that measurements of the speed of light done on earth have decreased over the past couple of centuries. But this decrease (which is disputed in any case) amounts to a few percent at most, so he must assume that the speed was much faster early in earth's history than it is now in order to bring light here from the most distant objects in just a few thousand years.16
But if the speed of light was only thousands of times faster early in earth's history than it is now, then Einstein's famous equation E = mc2 means real trouble. With c (the speed of light) only a hundred times larger in patriarchal times, c2 will be 10,000 times larger than now. Thus the sun, converting mass to energy at the same rate as today will fry the earth with 10,000 times the radiation. Alternatively, masses were 10,000 times smaller to compensate, and neither humans or air molecules were massive enough to keep from floating away from the earth. Obviously neither of these were the case, so it does not appear that the speed of light has changed in such a way as to avoid an old universe.17
The Isotropic Radio Background
Let us continue with our discussion of cosmological data. The development of radio telescopes (powerful receivers with giant antennas) after World War 2 led in 1964 to an important discovery by Arno Penzias and Robert Wilson. At radio wavelengths, the sky is not black but gray. Some sort of radio radiation is coming to us from all directions. It is very uniform in intensity, and is thus called "isotropic." It does not vary in intensity daily or seasonally. Therefore it must not originate in our solar system, galaxy, or even galaxy cluster, as we are off-center in all of these structures.
The spectrum of this radiation has been measured over a wide range of wavelengths, from just under a meter to well under a millimeter, more than 500 times the range of our visible spectrum. Throughout this range, the spectrum conforms almost exactly to that of a so-called "blackbody" (an object that perfectly absorbs all radiation falling on it, and re-emits radiation in a spectrum that depends on the body's temperature only) at a temperature just below three degrees above absolute zero. This radiation is therefore commonly known as "the three-degree (cosmic) blackbody radiation."
The isotropic nature and spectrum of this radiation fit very nicely into the scheme of the "big-bang" cosmologies to be discussed later. In such cosmologies, the radiation is seen to be the remnant of radiation from the universe as a whole at a time shortly after the big bang, when the universe first became transparent. The radiation has subsequently cooled due to the enormous expansion of the universe since that time. Cosmologist George Gamow predicted such radiation on the basis of big-bang cosmology some twenty years before it was actually discovered.
Early in the 1960s Maarten Schmidt and other radio-astronomers discovered a new class of astronomical objects which they named quasi-stellar radio sources, or "quasars" for short. The longer name tells us a bit about them: the objects look like stars through an optical telescope, and they probably would never have been noticed had it not been for their unusual brightness at radio wavelengths.
But it is the spectra of quasars that reveal their significance for cosmology. Quasars have redshifts which are greater than those of the most distant known galaxies. If these redshifts are due to the expansion of the universe, and if the expansion rate is linear with distance, then the furthest known quasars are about ten billion light-years away. Furthermore, if quasars are as far away as their redshifts indicate, then they are the most powerful objects in the sky, somewhat straining our imaginations to dream up energy sources for them. Present proposals include matter- annihilation, stellar collisions, or enormous black holes to provide their energy.
Of course, it is possible that quasars are not really so far away, but that their redshifts have another explanation. Astronomer Halton Arp has suggested that quasars are fragments blown off by exploding galaxies, but so far he has been unable to locate any blueshifted quasars to represent fragments blown in our direction. This is a serious problem for his view. Moreover, a number of quasars show secondary, smaller redshifts in their spectra, suggesting that some of their light has been absorbed by gas clouds between us and them. Since these smaller redshifts are still quite large, it looks like the quasars really are at the enormous distances that their redshifts indicate.
The Steady-State Universe
Shortly after the end of World War 2, the English cosmologists Hermann Bondi, Thomas Gold, and Fred Hoyle proposed what has come to be known as the steady-state cosmology. Accepting the evidence we have sketched above for a finite lifetime for stars and for a universe which is expanding, they yet claimed that the universe was infinitely large and had always existed. Instead of being static (like the model mentioned previously) or thinning out (like the big-bang cosmologies we will discuss below), the universe was proposed to be in a dynamic "steady state" in which the density of matter is kept constant by the expedient of adding new matter as the old matter moves away. This new matter is continually being added by a process of creation not the supernatural act of God, but the natural workings of an impersonal force. The new matter also serves to fuel new stars which are continually forming. Thus the stars we now see are only some billions of years old, but at any time back in the past (no matter how far) there have always been stars burning. The debris from burnt-out stars does not clog up the cosmos because the universal expansion carries it away.
Bondi, Gold and Hoyle claimed their cosmology was philosophically more satisfying than cosmologies with some sort of beginning (such as the big-bang cosmologies) because their theory satisfied the Perfect Cosmological Principle. This principle states that the universe, viewed on a sufficiently large scale, looks the same at all times, in all places, and in all directions. Competing cosmologies only satisfied the Cosmological Principle -- that the universe looks the same in all places and in all directions, but its appearance may change with time.
In spite of the fact that the steady-state theory postulated the violation of virtually every conservation law in physics (though all on a scale too small to detect locally), it enjoyed a considerable vogue until about 1965, when new observations began to press it severely. The most important of these observations were: (1) the three-degree blackbody radiation mentioned above, which was predicted by big-bang cosmologies but unexpected by the steady-state theory; (2) there are more quasars per unit volume at great distances (i.e., far back in the past) than nearby (recently), violating the Perfect Cosmological Principle.
Since 1965 Hoyle has retreated to a modified version of the steady-state theory which is beyond empirical test: we are in an expanding part of a universe that is steady-state on a scale so vast that we will never be able to observe it; other parts of the universe beyond observation are collapsing.18 With such a non-testable modification, few cosmologists are enthusiastic about the steady-state theory today.
Varieties of the Big-Bang Universe
Since the mid-sixties the big-bang theory has held the field as best fitting the available data of cosmology. Yet the big-bang theory is actually a group of several alternative theories. One way to sort them is: (1) the oscillating cosmology; (2) the single-bounce big-bang; and (3) the no-bounce big-bang. All three versions agree that the universe is presently expanding from an event which occurred some ten to twenty billion years ago the big-bang. At that time the universe began to expand from a highly compressed state with very great temperature (perhaps both density and temperature were infinite). Since then, the universe has been expanding and cooling. The quasars are some sort of object -- perhaps a special sort of galaxy -- that formed more easily earlier in the expansion. The blackbody radiation comes from even earlier, a remnant of the fireball at the time radiation and matter separated and the universe became relatively transparent.
The three varieties of big-bang cosmology differ on what the big bang was and what happened before it. The no-bounce theory was proposed first, in the 1920s, by George Lemaitre, a Belgian Roman Catholic astronomer, who apparently envisioned the big bang as the creation event. George Gamow later removed creation by suggesting that the big bang was rather a "big bounce." His one-bounce version proposed that the universe was a thin hydrogen gas from eternity past which gradually pulled itself together by gravity and then bounced; it has been expanding ever since, and will continue to do so forever. This theory was later modified into the oscillating cosmology, which sees the universe alternately expanding and contracting, with a big bang (bounce) every hundred billion years or so. It is this last version which is most popular today , both among cosmologists and in popular presentations, where Carl Sagan and Isaac Asimov have been especially active in promoting it. Let us examine these varieties in reverse order.
Problems with the Oscillating Cosmology
Since the oscillating cosmology sees the universe as alternately expanding and contracting forever, its problems (naturally enough) involve: (1) making an expanding universe stop and begin contracting; (2) making a contracting universe bounce and begin expanding; and (3) doing both forever. As the oscillating cosmology shares problem (2) with Gamow's one-bounce cosmology, let us look at the other problems first.
Forever is a long time! If there is any process in the universe as a whole which causes it to lose energy at a non-vanishing rate, the oscillating universe would long ago have ceased to oscillate. So for this model to work, the universe cannot be a finite amount of matter in an open, infinite space; otherwise the radiation will be lost on every oscillation. If, then, we assume that the universe is a finite amount of matter in a closed 3-D space, which expands and contracts in a 4-D space, we must also assume that none of the energy of expansion "leaks away" into the 4-D space. This seems to be a very unlikely assumption; we have no examples of energy confined to a 1-D or 2-D space which do not leak into 3-D.
Can the universe, then, have an infinite amount of matter? Perhaps. But getting an infinite amount of matter which is spread over an infinite volume of space to coordinate its activities so as to expand and contract in unison seems to be a tall order for natural laws to accomplish! And if we postulate a Coordinator, we might as well have a Creator.
So much for problem (3). Problem (1) is easily solved theoretically; all we need is a sufficient density of matter for its self-gravity eventually to overcome the expansion and turn it into a contraction. This is like throwing a ball up in the air and waiting until gravity pulls it back to earth. On earth, however, we have plenty of gravity but not much velocity for a hand-thrown ball; so naturally, the ball soon stops rising and begins to fall. If, however, we increase the velocity sufficiently by (say) shooting it up in a rocket at a speed faster than seven miles per second, it won't come back. Alternatively, if we throw the ball up from the surface of a small enough planet (say, at 70 miles per hour from the surface of an asteroid less than 20 miles in diameter), the gravity won't be strong enough even to stop a ball moving that slowly.
Well, which is the case for our universe? Is the matter density high enough to stop its expansion eventually or not? At present, it looks like the answer is that the expansion will not stop. We have only been able to locate something like one to ten percent of the density needed to stop the expansion, and astronomers have counted the visible stars, the total matter in and around galaxies, and the invisible hydrogen gas between galaxies. About the only candidates left are black holes between galaxies, the possibility that neutrinos are not massless, or undiscovered elementary particles with certain exotic characteristics.
For the oscillating cosmology, problem (1) may therefore be soluble, though it looks bad at present. Problem (3) seems insoluble without making very special and unlikely assumptions. As Jastrow suggests, the favor that the oscillating cosmology presently enjoys is probably more the result of a "religious" motivation -- a desire to eliminate creation -- than to any evidential merit of the theory.19
Problems for the One-Bounce Cosmology
Gamow's one-bounce cosmology postulates that the universe has always existed. From eternity past to about 10 to 20 billion years ago, it was rather dull a mass of hydrogen gas gradually pulling itself together by means of gravity. At the big bang it bounced, and since then it has been expanding, forming galaxies, stars, planets, life, etc., all of which will one day "die," though the universe will continue to expand forever as a collection of dark and lifeless cinders. This theory has not been nearly a popular as the oscillating model, though perhaps it is reflected in T. S. Eliot's poem about the world ending, "not with a bang but a whimper."
The one-bounce theory avoids the oscillating cosmology's problem (3) with energy loss, as no eternally-repeating cycle is envisioned. It does have a problem of its own with eternity. It also avoids problem (1), as the one-bounce universe never stops expanding once it starts. It does share problem (2) with the oscillating cosmology, which we must examine.
Let us first look at the one-bounce theory's problem with eternity. Gamow postulates that for an infinite period of time the universe is contracting towards the big bounce. This involves a contraction rate that is zero at eternity past and gradually increases in just such a way as to take an infinite time to accomplish a finite action. This is easily arranged mathematically by means of an asymptotic function, but it is questionable whether it could ever be arranged physically without a supernatural Arranger. The slightest non-uniformity in the mass distribution will produce local contractions at a substantial rate instead, breaking the universe into smaller and smaller contracting regimes.
On to problem (2): can a contracting universe "bounce" so as to begin expanding? More seriously, can a universe which must contract to such high densities and temperatures as will produce the big-bang fireball, subsequently bounce? The cosmological equations of Einstein and Friedmann have a mathematical singularity at the hoped-for bounce point, indicating the temperature and density would go to infinity. Is this over-idealized? Attempts to avoid this problem by introducing irregularity do not appear to work.20 This agrees with our present knowledge of physical forces, where at very high densities gravity (which is only attractive) overcomes the repulsive elements in the nuclear and electromagnetic forces and pulls everything into a black hole from which there is no escape. Asimov would like to think that our whole universe is a black hole, but he has still not succeeded in explaining why its matter should "bounce" when highly compressed rather than forming still another black hole.21
Of course, one can postulate some unknown force that saves the theory just in the nick of time, like the old melodramas! by introducing a repulsion strong enough to overcome gravity but which comes into play only at densities and temperatures high enough to produce the big-bang fireball. Jastrow, however, argues that even this is insufficient.22 Such a repulsive force, he says, will have an equivalent potential energy E, and this energy, by Einstein's equivalence formula E=mc2, will function like a mass m. This mass, when added to the mass already present, will strengthen the gravitational force enough to overcome the repulsive force, so that the whole will still collapse into a black hole! Thus big-bang cosmologies employing a bounce seem to be fatally flawed unless one postulates a very special repulsive force that does not obey Einstein's mass-energy equivalence principle.
Lemaitre's No-Bounce Cosmology
The original form of the big-bang theory avoids the problems discussed above. By having creation at the big bang, neither a contraction nor a bounce is needed. The theory has enough flexibility to fit an ever-expanding universe or one which eventually contracts. Eternal activity is transferred "outside" the universe to God the Creator rather than remaining in the physical laws and causing the problems faced by the various non-supernatural cosmologies we have discussed.
A Note on the Gott-deSitter "Big Bubble" Universe
Just this January (1982) J. Richard Gott of Princeton University proposed a radically new cosmology which he hopes will replace the big-bang model as standard.23 As yet it is too early to tell whether his hope will be realized. Gott agrees that our "universe" began at the big bang without a previous contraction. But he suggests that our universe is only an expanding "bubble" in an infinitely old and large deSitter universe. This larger "outside" universe is postulated to contain nothing but radiation, but the radiation is at an unbelievably high temperature and pressure (5x1031 deg K and 3x1093 g/cm3). The matter in our universe, Gott says, condensed out from radiation entering the bubble at its beginning. The bubble will continue to expand forever. The high temperature and pressure of the big bang is a reflection of the conditions in the "outside" universe. The isotropy of our universe and its big bang is also a reflection of the isotropy of radiation in the deSitter universe.
The mathematics and geometry of this proposal are sufficiently complex to make physical intuitions and quick critiques difficult. For instance, it would seem to me that the enormous external radiation pressure would inhibit expansion of the bubble; perhaps this could be solved by having the bubble boundaries be relativistic horizons. Nevertheless, let us note that to avoid a Creator, this cosmology must postulate the existence of an infinite and eternal exterior "force" to explain our visible universe. The big difference between this model and creation is the impersonal nature of its "creator," the deSitter universe. But it is just this impersonality which raises the question of whether an isotropic and energetic radiation field can really explain the organized complexity that we know exists in our actual universe.
We have completed our rather sketchy survey of the data and theories of modern cosmology. What can we say in conclusion?
What does it mean to choose the simplest hypothesis? Surely, not to choose one so simple that it doesn't fit the data. And the data of cosmology cannot finally exclude the fact that the universe we actually inhabit contains life, and humans, and the Bible. The evidence of extremely complex design found in living things25 (especially in the human mind), and the evidence of the moral sphere in humans,26 argue that this infinite, eternal power behind the universe is more like a mind than a force. Though well outside the scope of this paper, there is quite adequate evidence that this mind is the God of the Bible.27
How do our conclusions square with the Bible? Like the cosmological evidence, the Bible pictures the universe as immeasurably large (Jer 31:37; 33:22; Ps 8:3-4) but apparently finite (Ps 147:4). It is also described as created by the infinite, personal God of the Bible (Gen 1:1 and elsewhere) and running down (Ps 102:26-27; Heb 1:10-12). The major problem regards the age of the universe. The Bible has been traditionally understood to teach a recent creation, and this is the main reason for the strength of the young-earth creationist movement in evangelical circles today. Yet it is imperative that we realize that the Bible itself nowhere indicates that the earth is young, that the days of Genesis 1 are literal and consecutive, or that the genealogies of Genesis 5 and 11 should be added up to give a complete chronology. As I have sought to deal with these matters in my book Genesis One and the Origin of the Earth (see endnote 24), I refer the reader there for a more detailed discussion. An earth and universe some billions of years old is not taught explicitly in the Bible, but it is not in disagreement with a fair and reasonable interpretation of the biblical creation account.
Note added in 1997 reprint: I have made little attempt
to update this discussion, and a lot has happened observationally and
in 15 years. The accumulation of further evidence for a big bang has
well dispatched the steady-state theory, and the oscillating and
big-bang models have been abandoned. Some variety of a big bang in
our universe started 10-20 billion years ago now dominates the field,
many cosmologists seem to be hoping it is some kind of bubble in an
eternal universe. Excellent discussions of this material can be found
two recent books by Hugh Ross.28
1. Hannes Alfven, "Cosmology, Myth or Science?" in Cosmology, History and Theology, ed. Wolfgang Yourgrau and Allen D. Breck (New York and London: Plenum Press, 1977), pp 12-13.
2. Robert C. Newman, "Pascal's Wager Re-examined," Bulletin of the Evangelical Philosophical Society 4 (1981), 61-67; tract You Bet Your Life! (Hatfield, PA: IBRI, 1991).
3. Excepting luminous gas -- which occurs in galaxies -- and quasars, which may or may not be a special type of galaxy.
4. A light-minute is the distance light travels in one minute, about eleven million miles. A more common unit for measuring distances in astronomy is the light-year, about six trillion miles.
5. The explosive power of nuclear weapons is measured by the equivalent weight of TNT needed to produce an equal blast. A megaton is one million tons.
6. Harold Camping, "What is the Size of the Universe?" (Oakland, CA: Family Radio, 1981).
7. Parry Moon and D. E. Spencer, "Binary Stars and the Velocity of Light," Journal of the Optical Society of America 43 (1953), 639.
8. Harold Slusher, Science and Scripture (Mar-Apr 71), 22; John C. Whitcomb, Jr. and Henry M. Morris, The Genesis Flood (Philadelphia: Presbyterian and Reformed, 1961), 369-70; Robert E. Kofahl and Kelly L. Seagraves, The Creation Explanation (Wheaton: Harold Shaw, 1975), 154.
9. Jean-Pierre Vigier, "Cosmological Implications of Non-Velocity Redshifts A Tired-Light Mechanism" in Cosmology, History and Theology, 141-57.
10. Robert Jastrow, God and the Astronomers (New York: W. W. Norton, 1978), 27-28.
11. Robert C. Newman, "Hierarchical Cosmologies: A New Trend?" Journal of the American Scientific Affiliation 24 (1972), 4-8; judging from the 25 years since this article appeared, they didn't become a trend!
12. Whitcomb and Morris, Genesis Flood, 369; Henry M. Morris, The Genesis Record (Grand Rapids: Baker, 1976), 65-66; Kofahl and Seagraves (Creation Explanation, 154) recognize problems here; so does Paul M. Steidl, The Earth, the Stars and the Bible (Phillipsburg, NJ: Presbyterian and Reformed, 1979), 222-23.
13. Trevor Norman and Barry Setterfield, The Atomic Constants, Light and Time (Australia: Flinders University, 1987); Steidl, Earth, Stars and Bible, 223-24.
14. Donald H. Menzel, Fundamental Formulas of Physics, 2 vols. (New York: Dover, 1960), 1:149, 151; 2:454, 460, 545.
15. Fred Hoyle, Astronomy and Cosmology (San Francisco: W. H. Freeman, 1975), 586-87.
16. Norman and Setterfield, Atomic Constants, Light and Time.
17. Robert C. Newman, "An Ancient Historical Test of the Setterfield-Norman Hypothesis," Creation Research Society Quarterly 28 (1991), 77-78.
18. Fred Hoyle, Galaxies, Nuclei and Quasars (New York: Harper and Row, 1965).
19. Jastrow, God and the Astronomers, 27-28, 111-16.
20. Robert H. Dicke, Gravitation and the Universe (Philadelphia: American Philosophical Society, 1970), 66-67.
21. Isaac Asimov, A Choice of Catastrophes (New York: Simon and Schuster, 1979), 68-69.
22. Robert Jastrow, Until the Sun Dies (New York: W. W. Norton, 1977), 28-29.
23. D. E. Thomsen, "Cosmic Cauldron Bubbles Up Universe," Science News 121 (1982), 116; M. Mitchell Waldrop, "Bubbles Upon the River of Time," Science 215 (1982), 1082-83.
24. Some of the considerations for a detailed age are discussed in chapter one of Robert C. Newman and Herman J. Eckelmann, Jr., Genesis One and the Origin of the Earth (Downers Grove, IL: InterVarsity, 1977; reprint Hatfield, PA: IBRI, 1991).
25. e.g., Encyclopaedia Britannica (1970) s.v. "Life" by Carl Sagan, notes that the information content of the simplest living cell is equivalent to 100 million pages of the Encyclopaedia Britannica.
26. On brain complexity, see the concessions by Carl Sagan, Dragons of Eden (New York: Random House, 1977), 46, 212; on the moral sphere in humans, see C. S. Lewis, Mere Christianity (New York: Macmillan, 1953), book I: "Right and Wrong as a Clue to the Meaning of the Universe."
27. See, e.g., John Warwick Montgomery, ed., Evidence for Faith: Deciding the God Question Dallas: Probe/Word, 1991); Robert C. Newman, ed., The Evidence of Prophecy (Hatfield, PA: IBRI, 1994).
28. Hugh Ross, The Fingerprint of God, 2nd ed.
CA: Promise Publishing, 1991); The Creator and the Cosmos, 2nd
(Colorado Springs: NavPress, 1995).
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