Cosmology as a Science

From the Covalence Archives

Cosmology as a Science and as a Worldview1
by George L. Murphy, St. Paul’s Episcopal Church, Akron OH and Trinity Lutheran Seminary, Columbus OH  

 
Introduction

“The cosmos is all that is, or ever was, or ever will be.” Many people will recognize Carl Sagan’s introduction to his Cosmos television series. Cosmology is now understood to be the branch of science that studies the universe as a whole, and Sagan’s program was an introduction to this discipline. But those words were also an implicit statement of a worldview in which there is nothing beyond the physical universe.

We can distinguish two levels of cosmology. The scientific study of the universe as a whole might be called cosmology with a small c while a view of the universe in its relationships with all of reality is Cosmology with a capital C. For some, like Sagan, the two are the same. For Christians and others who believe that the universe is the creation of a God who in some sense transcends the world, the two must be distinguished. And the ways in which a person’s small c and big C cosmologies interact will be significant.

Like all sciences, cosmology has theoretical and observational aspects. Observers try to find out more or less directly about the universe that we inhabit, while theorists construct “model universes” based on some physical theory. Those models may help to elucidate the theories, but the primary goal is development of a model that corresponds to the real universe and predicts new features of it. However good the fit may be, it’s always important to distinguish the model and reality, the map and the territory.

Scientific cosmology tries to give us “the big picture.” A theological Cosmology, on the other hand, tries to give us “the biggest picture” which includes God’s origination of, activity in, and purpose for, the cosmos. In doing this it should do justice to the Judaeo-Christian tradition of reflection on these matters, but it must also take seriously what scientific cosmology has learned about our world.

And it has learned a great deal. We know that our universe began in a hot big bang about 13.7 billion years ago and that basic particles and light atomic nuclei were formed in the first minutes of expansion from that explosion, an expansion that still goes on. The properties of the universe suit it with remarkable precision for the emergence of life. But there is a lot that we don’t know. The first fractions of a second of the big bang remain grounds for debate between various theories. We actually understand only about 4% of the material content of the universe, the remainder being the “dark matter” which binds galaxies and clusters of galaxies and the even more puzzling “dark energy” whose negative gravitational effect is accelerating cosmic expansion.

There remains much to learn, and the worldviews of scientists – their Cosmologies – may help them to find answers or may hinder them. Before we look at some current possibilities, it will be instructive to consider a few historical examples of the ways in which the two levels of cosmology have influenced one another.

Three Twentieth Century Moments

Scientific cosmology can be said to have begun in 1917 when Albert Einstein first applied his new theory of gravitation, general relativity, to the problem. At that time the status of the “spiral nebulae” was still unclear. We now know them to be galaxies like our own Milky Way but at that time some astronomers thought them to be within the Milky Way, which was the entire universe. Only a few spectra of these nebulae had been measured. In addition, there was a long-standing belief that the universe on the whole was static and unchanging. Thus it was reasonable for Einstein to try to develop a static cosmological model from his theory.

But he may have had another motive. Einstein was a pantheist, a great admirer of Spinoza who held that “God” and “the universe” were the same – deus sive natura. Max Jammer, in his excellent discussion of Einstein’s beliefs2, suggests that this pantheism may have strengthened Einstein’s desire to find a static universe – for if the universe and God are equivalent, and if God is immutable, then the universe is immutable. Einstein found that such a model required a modification of his field equations, an addition of a “cosmological term” which represents a repulsive aspect of gravitation to balance the ordinary gravitational attraction of matter.

Within a few years, however, it became clear that the universe wasn’t static. Hubble found that there was a linear relationship between the redshifts in the spectra of galaxies and their distances, a relationship whose most natural interpretation was that the galaxies were all receding from us, the redshifts being an indication of their speeds. Einstein’s theory without the cosmological term could accommodate this, but the simplest explanation was given by the British astrophysicist E. A. Milne. He pointed out that if all the galaxies had exploded out from a point at some instant in the past with speeds ranging from zero to that of light, the ones moving fastest would of course have by now gone the farthest. In the 30s and 40s Milne and others developed this simple idea into a detailed and influential theory of “kinematic relativity.”

Milne’s cosmology had its start in the fact of galactic redshifts, but his concept of an instantaneous point origin of the cosmos was also in accord with what he said at the end of his last book, that as a member of the Church of England “I do most fervently believe that this universe was created by Almighty God.”3 Milne’s theory was controversial for several reasons and one history of modern cosmology suggests that in the view of other scientists, “Milne’s position was unnecessarily worsened by the strain of argument found in his last book”.4 Perhaps, but he may just have been more explicit about the importance of his Cosmology for his cosmology than some other scientists.

It might seem obvious that a universal recession of galaxies implies that they were once much closer together, but in the mid 40s there were reasons to look for alternative models. Due (we now know) to errors in determining galactic distances, the time elapsed since the beginning of the expansion seemed to have been something less than two billion years, and the earth’s crust was known to be older than that. Clearly the earth should not be older than the universe!

The Steady State theory of Bondi, Gold and Hoyle solved this problem in a simple but radical way. They proposed that the universe, while always expanding, always remains the same. Matter does not thin out because it is continually created and condenses into new galaxies, so that the cosmos always has the same overall appearance. (Hoyle introduced a “creation field” term into Einstein’s equations to account for this.) The Milky Way happens to be somewhat older than the average galaxy but the earth is not older than the universe because the universe has always existed.

The Steady State theory solved the “time scale problem” and had other attractive features5. For those like the scientists who developed the theory and were uncomfortable with the similarity between a beginning of cosmic expansion and traditional religious pictures of a “creation instant,” it also had the advantage of removing that disturbing image. The fact that anti-religious views helped to support steady state views is shown by the continued adherence to the theory by many scientists even after the time scale problem was removed by improved measures of galactic distances.

The models of Einstein, Milne and the Steady State theory have all been found wanting. The universe is not static as Einstein originally thought, its expansion isn’t uniform as Milne’s theory requires, and the microwave background radiation shows that, contrary to steady state assumptions, the universe was much hotter and denser in the distant past. But these theories may still make a positive scientific contribution. Einstein’s cosmological term gives one model of the dark energy that is now thought to pervade the universe and Milne’s theory provides a useful, though oversimplified, picture of cosmic expansion for introductory expositions.

The Steady State theory has a different legacy. Big Bang theorist George Gamow wanted to show that all atomic nuclei were formed by fusion reactions in the hot dense conditions of the very early universe, so rival Steady State proponents, who couldn’t appeal to a Big Bang, had to provide an alternative. Hoyle and his collaborators developed a theory in which carbon and heavier nuclei were formed in stellar interiors. We know now that only the lightest elements could be built up in the rapidly expanding early universe. While the Steady State theory has been relegated to history, the theory of stellar nucleosynthesis that it motivated is now a well-established part of astrophysics. Religious or anti-religious worldviews can have a variety of effects on scientific theories.

But we should remember theological as well as scientific analysis. It is easy for Christians to see problems with pantheism or attempts to eliminate anything that resembles a biblical account of creation, but Milne’s rationalistic approach also created difficulties. He argued that the universe had to originate at a single point in order to have an instant of creation because relativity rules out absolute simultaneity for spatially separated events. In other words, God had to create a universe consistent with the theory of relativity. This contrasts with the idea that Thomas Torrance has emphasized, that because of God’s freedom, the universe, while rational, is contingent.6 God could have made a universe that had another kind of rationality.

This Christian concept of the contingent rationality of creation doesn’t try to specify details of the universe but should make us wary of current attempts to show that only one set of physical laws, or one kind of universe (or multiverse) is possible. The answer to the question that Einstein said interested him most, whether God had had any choice when he made the universe, is “Yes.”

The Creation of the Universe

The model universes of general relativity that are at all like our real world are “singular,” or incomplete. It is as if the event which might be labeled “t = 0” were torn out of space-time. (As Gertrude Stein said in another context, “There’s no there there.”)

Some writers have tried to equate this singularity with the “beginning” of Genesis 1:1 and the doctrine of creatio ex nihilo.7 Others have tried to eliminate, modify or get behind the singularity, perhaps with a theory of quantum gravity. This can be a legitimate scientific enterprise with no anti-religious motives. (It was, in fact, the topic of my first published physics paper.8) But, as with the Steady State theory, such work may be an attempt to close what is seen to be a loophole for religion. For example, after describing the interesting “no boundary” model universe which he had developed with James Hartle, Stephen Hawking asks rhetorically, “What place, then, for a creator?”

Theological reflection over the past two thousand years should warn us away from the notion that the doctrine of creation requires the Big Bang to be the last word of scientific cosmology. “Creation” can mean at least two things. It may mean (1) that the universe ultimately depends upon God. It can also refer to the idea that (2) through God’s action the universe had a temporal origin, “with time” though not “in time.”

It’s possible to hold to (1) without (2), though that is not the most obvious way of understanding Genesis 1:1. In this case God’s ongoing preservation is the answer to the question “Why does any universe at all exist?” But this doesn’t mean that we have to give up on (2). Perhaps our universe did have a temporal beginning 13.7 billion years ago when God “breathed fire into the equations.”10 Science has some limits, and perhaps this is one of them.

Cosmic Purpose

In recent years the focus of science-theology dialogue has shifted from an almost exclusive focus on origins – Alpha – to give some attention to the purpose and final state of the universe – Omega. One thing that has stimulated discussion of cosmic purpose is the so-called “anthropic coincidences” and various “anthropic principles” which have been based upon them. These begin with the observation that the parameters of the physical universe, such as its age and the strengths of its interactions, seem to be “just right” for the evolution of intelligent life. Perhaps, some have speculated, the universe had to bring forth intelligence.

One religious response has been to see anthropic principles as a support for the argument from design. If the universe is finely “tuned” for life then, the argument goes, there must be a “Tuner.” But others counter with the idea that our world is just one of a vast ensemble of universes all having different properties, and ours just happens to have the right properties for intelligent life. There seems no purely logical way to choose between these two possibilities.

There is some force to anthropic design arguments but more profound ideas can be pursued which we can find by asking about the purpose of creation as a theological question. We have no business imposing speculative constraints upon God, but we can note what the Bible says. When Ephesians 1:10 speaks of God’s “plan for the fullness of time, to gather up all things in him [Christ], things in heaven and things on earth,” and when Colossians 1:16 says that “all things” were created not only “through” Christ but “for” him, we are pointed to the idea that the Incarnation is the purpose of creation. And in fact a thin but significant tradition whose most prominent modern exponent was Karl Barth has held that the becoming flesh of the divine Logos was not simply a “Plan B” to deal with sin (though it does do that) but God’s intention from the beginning.

If this is so then the universe must, with divine cooperation, evolve life and intelligence: There must be suitable carne in which the Word can be incarnated. The purpose of creation is not simply the anthropos but the theanthropos, the divine human, And we can speak of the doctrine of the Incarnation as a Theanthropic Principle. Such a principle is not a scientific claim any more than scientific anthropic principles are theological doctrines. One is based on the apostolic witness to Christ and the other on the observed values of physical parameters and scientific theories. But the two lines of argument may be mutually supportive.

The Last Things

Recent observations that indicate that cosmic expansion is speeding up imply that the universe will continue to thin out and cool down forever. Even if there is a possibility for continuing life, in the sense of ongoing information processing, it is hard to discern anything like the hopes of Christian eschatology – the resurrection of the dead, the vindication of God’s work and the reign of God.

That argument makes the commonsense assumption that the future evolves from the past, in a statistical if not a deterministic sense. And if that is true then nothing genuinely new can emerge. But is it true?

In recent theology there has been considerable emphasis on the concept of prolepsis, “the invasion of the present by the power of what is yet to come.”12 The future is seen not merely as what evolves casually from the past or even as just bringing something new but as having a real impact on us before it completely arrives. In particular, the resurrection of Jesus is a prolepsis of God’s final future. If the universe is in some sense created from a future which is centered on Christ then it is not surprising that the properties of the universe suit it for the development of intelligent life.

Does this concept of prolepsis correspond to anything in science? Maybe. There has been a good deal of discussion by physicists about time travel and the possibility of sending signals into the past. The advanced potentials of classical electrodynamics, tachyons, “time machine solutions” of Einstein’s field equations (such as Gődel’s model universe) and some models of dark energy have been considered. 13

Again, physics is not theology and theology is not physics. Each has its own reasons to pursue these ideas. But physics and theology can motivate one another. The concept of prolepsis can encourage scientists to investigate physical possibilities for retrocausation. In turn, scientific ideas about time travel can provide analogies for theology in talking about the resurrection – the type of thing Paul does with first century examples in I Corinthians 15:35-41.

Chiasmic Cosmology

I believe that we should place our scientific understanding of the universe in the context of a theology of the cross, and with that idea in view have pursued a program that I have called “chiasmic cosmology.”14 This is a capital C Cosmology, not a scientific theory. It is an attempt to see the presence and activity in the universe of the God who has been made known to us in the cross of Christ. As Irenaeus said some 1800 years ago, “The Son of God was crucified for all and for everything, having traced the sign of the cross on all things.” 15

Since God is revealed most fully in the God-forsakenness of Calvary we may expect God’s presence and work in the universe to be hidden. God acts continually through the natural process which science studies, which therefore serve (in Luther’s phrase) as “the masks of God” which hide God from our direct observation. That is true today, as God provides us with daily bread, and it was true in the past. As we look farther and farther back into the past we see the evolution of living things and the chemical reactions which somehow gave rise to life, the condensation of matter into planets, stars and galaxies, the electroweak and strong interactions which formed atoms, atomic nuclei and elementary particles, and perhaps the origin of matter and space-time itself by quantum gravitation, all as the work of God and as the veil which hides the creative hand and Word of God from us.

In this view the spectacular map by the Cosmic Background Explorer of temperature fluctuations in the microwave background which definitely confirmed the reality of the Big Bang was not, as the scientist in charge of the project suggested, “the face of God” but one of God’s masks. Bonhoeffer said that “From the beginning the world is placed in the sign of the resurrection of Christ from the dead,” and it is because of faith in the God who raised the crucified Christ that we hold that the same God is the source of all things.”

References

1. This is a revised version of a talk given at the fourth Sunday Scientist Symposium sponsored by the ELCA’s Alliance for Faith, Science and Technology in Carefree AZ, 12-14 October 2007.

2. Max Jammer, Einstein and Religion (Princeton University, Princeton NJ, 1999), pp.62-63.

3. E.A. Milne, Modern Cosmology and the Christian Idea of God (Clarendon, Oxford, 1952), p.160.

4. J.D. North, The Measure of the Universe (Dover, New York, 1990), p.173.

5. A excellent presentation of a steady state view is D. W. Sciama, The Unity of the Universe (Doubleday, Garden City NY, 1959).

6. Thomas F. Torrance, Divine and Contingent Order (Oxford, New York, 1981).

7. Hugh Ross has been a strong proponent of such arguments. See, e.g., his The Fingerprint of God (Promise, Orange CA, 1989), Ch.12.

8. George L. Murphy, "Big Bang Model without Singularities," Physical Review D8, 4231, 1973.

9. Stephen Hawking, A Brief History of Time (Bantam, New York, 1988), p.141.

10. Cf. Hawking, A Brief History of Time, p.174.

11. A recent discussion is Paul Davies, Cosmic Jackpot (Houghton Mifflin, Boston, 2007).

12. Ted Peters, God: The World’s Future, 2d ed. (Fortress, Minneapolis, 2000), p.320. See also his Anticipating Omega (Vandenhoeck & Ruprecht, Goettingen, 2007).

13. Some possibilities are discussed in Paul Davies, How to Build a Time Machine (Viking, New York, 2002).

14. George L. Murphy, The Cosmos in the Light of the Cross (Trinity Press International, Harrisburg PA, 2003).

15. This statement from Irenaeus’ On the Apostolic Preaching, was quoted in this form by P. Evdokimov in Scottish Journal of Theology 18.1, 1965, p.5.

16. Dietrich Bonhoeffer, Creation and Fall/Temptation (Macmillan, New York, 1959), p.19.