A Finely-Tuned Universe
Whether experiencing nature’s web in a pristine mountain glade or peering at the wonders of a working cell, evidence of an intricately functional universe is everywhere. The beautiful and elegant descriptions used of nature are exactly those used by cosmologists to describe the equations for the expansion of the universe. Equally surprising is that the mathematical equations that describe the universe’s development are few and simple, the kind of equations whose discovery earns Nobel prizes.
Scientists commonly speak of equations having beauty despite the fact that no definition of beauty exists in science. Collectively, scientists agree on what constitutes a beautiful equation, an ingenious chemical reaction, or an elegant design because as humans, people see beauty in the world—the delicate lines in a face, intense colors of sunset, and the wonder of seeing a child being born. Scientists are as passionate as artists but operate within a discipline that strives for complete objectivity. Science is inherently focused on explanations of how the world works, but scientists, as people, are much more interested in understanding the meaning of the results. Einstein’s conclusion to his first paper on general relativity captures this personal essence: “Scarcely anyone who fully understands this theory can escape from its magic.”3
The universe not only has a beautiful mathematical structure but the equations and values are very finely tuned. Just four basic forces affected the first particles during the initial stages of the Big Bang: gravity, electromagnetism, the strong nuclear force, and the weak nuclear force. The balance between these forces is extremely precise in two ways: first the physical constants of the universe have very specific values, and second, the initial “boundary” conditions for the universe are tightly specified. Boundary conditions refer to the starting or developing nature of the universe, such as the delicate poise between expansion and collapse, and the fluctuations that form galaxies without forming black holes. Cosmologists like to say that the universe seems quite finely balanced between the outward energy of expansion and the inward pull of gravitation. Like shooting hoops, the force and trajectory must work together.
Fine tuning is nicely illustrated in the life of a star. Stars get their energy by burning hydrogen to form helium. When all the hydrogen is consumed, the core of the star pulls together under extreme gravity to form beryllium. Beryllium is a toxic element lacking the right bonding properties for most living organisms but is very efficiently converted to carbon (~100 percent), because there is just the right relationship between the electromagnetic and nuclear forces of beryllium and carbon. The energy for the conversion of beryllium into carbon is very closely matched so that if the conversion were only 4 percent higher or 0.5 percent lower, virtually no carbon would form. Carbon, once formed, can be consumed through a carbon-helium collision whose energy is similarly highly controlled; a deviation of only half a percent would lead all the carbon to be converted to oxygen. Carbon is slowly converted to oxygen, gradually enough to allow carbon to build up, but at a rate sufficient to produce oxygen for life. A series of delicately poised transformations provides a way for carbon to be produced from stars to provide “the building block for life.”
If the value of the gravitational constant was slightly larger, then the stars’ lifetimes would be much shorter with much less time for planets, and life, to evolve. Alternatively, weak gravity would mean that the stars could not generate enough heat to grow and explode to liberate the heavy atoms needed for life. How finely balanced is the force of gravity? Estimates for the allowable variation are in the range of 1 part in 100,000,000,000,000 (one hundred thousand billion).
Another example of fine tuning is the attractive force between two large masses. If this were just a little stronger, the force between the earth and the sun would be too strong and cause them to collapse into one body. If the force was just a little less, the world would spin off away from the sun. In either case the earth would not be properly warmed by the sun, and life would be unable to evolve. Owen Gingrinch, Harvard astronomer and historian of science, interprets this as follows: “Had the universe exploded with somewhat greater energy, it would have thinned down too fast for the formation of galaxies and stars. . . . Had the energy been somewhat less, gravity would have quickly got the upper hand and pulled the universe back together again in a premature Big Crunch. Like the Little Bear’s Porridge, this universe is just right.”4
Particle physicists at the supercollider in Switzerland recently found the elusive so-called “God particle.”5 Perhaps the most surprising thing about this discovery is that finding the God particle was not actually surprising. Theorists predicted the existence of a particle accounting for the attraction between different mass units almost fifty years beforehand. What was surprising is the precise mass of the Higgs boson and the associated Higgs field. If the Higgs field was slightly stronger atoms would start to shrink and neutrons would decay leading ultimately to hydrogen as the only stable element. The ramifications of finding the Higgs boson and the Higgs field will keep particle physicist occupied for many years, but as quantum physics probes ever deeper into the structure of the atom, the fine tuning continues to be an integral part of the universe’s structure.
The influence of philosophical ideals and scientific theory is ironically captured in the work of one of the leading physicists Fred Hoyle. Hoyle preferred to believe in the universe’s eternal existence—a steady state universe—because he held strongly atheist beliefs. Hoyle showed that the light elements, particularly hydrogen, helium, and deuterium, could be formed from nuclear reactions early in the universe’s existence. The intense temperatures permit nuclear fusion through particle collisions at high speeds to form the first elements of the periodic table, hydrogen and helium. Ironically, Hoyle’s calculations showed that the exact amount of existing helium was best accommodated by Big Bang cosmology rather than his own favored theory of the universe’s eternal existence. Hoyle’s conclusion: “There is a coherent plan to the universe, though I don’t know what it’s a plan for.”6
The mathematical form and values of the universal equations are not the only examples that cause scientists to say that the universe is finely tuned. The density of the universe is also strictly specified to a precision between 10–56 and 10–60, the equivalent of hitting a bull’s eye at a target twenty billion years light years away on the opposite side of the universe. Hoyle, an atheist, was so stunned by the coincidences that he wrote: “If this were a purely scientific question and not one that touched on the religious problem, I do not believe that any scientist who examined the evidence would fail to draw the inference that the laws of nuclear physics have been deliberately designed with regard to the consequences they produce inside the stars . . . .”7
Evolutionary biologist Richard Dawkins views the fine tuning of the universe differently. His book The Blind Watchmaker is subtitled “How the Evidence of Evolution Reveals a Universe without Design.”8 Dawkins rejects the idea that fine tuning is suggestive of a coherent plan, claiming that is instead how he would expect an evolving universe to be. The key issue is the interpretation of fine tuning in the universe; is this best explained as design imparted by God, or do godless naturalistic processes provide a better explanation for this seeming design?
Cosmic Recycling
Stars burn hydrogen and helium at their cores but eventually run out of fuel and burn out. Toward the end of a giant red star’s life, the intense heat and pressure fuses hydrogen and helium to produce the heavier elements—carbon, oxygen, magnesium, silicon, iron, and sulfur—that comprise more than 96 percent of earth’s mass.
Roughly