The Evidence from Physics and Cosmology (Part 1)

(This continues my previous posts about the evidence for a rational power at work in the universe.  This part will describe the evidence from the “Big Bang” creation and will emphasize the orderliness of the creation process despite images of a chaotic creation conjured up by the appellation, “Big Bang.”)

If you do any physical activity at all – even lifting a glass of water to drink – then you have an intuitive grasp of the laws of physics.  If you play sports, drive, walk or run, you know about speed, time and distance.  You already know how fast to stop or which way to turn to avoid a collision.  If you can keep your balance, you have an intuitive grasp of gravity.  This knowledge is built-in probably from evolution, but also from experience.  You know that the world is a very ordered place and that the physical laws of nature have consequences.  There are events and causes for events; time always moves forwards, never backwards; energy is necessary for life; causes always precede effects.

We have evolved to have this intuitive understanding of physics and to learn from experience in order to improve our physical abilities.  If that is all the evidence you need to indicate a likely rational power in the universe, then you can skip the sections on physics.  But let me pose one question: If evolution has built in some hard-wired comprehension of physical law, what about our mathematical understanding of physics?  Where did that come from?  Few people are born with or have acquired the abstract reasoning to understand the physical laws.  It is a difficult process to apply abstract mathematical models to our universe, and those models lead to some very counterintuitive explanations for the deep reasons the universe is the way it is. And the most surprising of all is that our best models have been confirmed by experiment.   If you are willing to ponder these questions, read on.

One of the key discoveries in the twentieth century was the discovery that the universe was expanding.  Prior to the twentieth century, the universe was assumed to be static.  Albert Einstein, when he was completing his work on the theory of general relatively, believed that the universe was static.  Yet, his equations predicted that the total mass of the universe should lead to a contraction of the universe.  So he added a term to his equations called the “cosmological constant” term in order to counteract the contraction.  When the scientific community began to accept the new observations that the universe was expanding, Einstein realized that he had changed his equations because of an unwarranted assumption about the universe.  The cosmological constant has proved useful, but Einstein called this change in his original equations as his greatest blunder.  Einstein considered it a blunder not because the cosmological constant wasn’t warranted, but because he had put it in for the wrong reason.

In the Nineteenth century, the assumed static universe led to another puzzle.  Since it was assumed that the static universe had always existed, the puzzle was why hadn’t the stars burned themselves out?  (There are serious philosophical issues with infinite past time, but those won’t detain us here.)  Various answers were put forth to attempt to deal with this problem, but it wasn’t until the early twentieth century that astronomers began to observe other galaxies in the universe.  Not only were there other galaxies besides the Milky Way, but they were moving away from us.  And not only were they moving away from us, but the further they were, the faster they were moving!

When cosmologists projected the expanding universe backward in time, it led to the theory that the universe began as a very tiny region that rapidly grew in size until it was the size it is today.  This theory was somewhat capriciously called the “Big Bang” theory.  The beginning wasn’t an explosion, however, but a very fast and very orderly expansion.  The projected beginning time is now set at about 13.7 billion years ago.  Thus there was a direct, simple answer to the nineteenth century question:  the stars hadn’t burned out because they were still very young. The “Big Bang” did not become the accepted consensus until the second half of the twentieth century.

I used the word ‘orderly,’ above, because our current understanding of atomic physics agrees very well with observations from the early universe.  In other words, almost from the very beginning, as we now understand it, the universe has behaved according to a set of laws that undergird all of physical reality.  What is particularly amazing is that the various laws of physics worked together to produce the universe we now have.  We currently have no model of a unified theory that includes both Quantum Theory and Gravitation, but both sets of laws worked to produce a universe with the right fuel for stars to burn provided that the fuel could be ignited by the force of gravitation.

The evidence for the Big Bang theory comes from astronomical observation and from verified theories of atomic physics.  We can actually capture some observational evidence that originated about 300,000 years after the universe began when we observe the cosmic microwave background radiation (CMBR) which forms an opaque horizon beyond which we cannot currently see.  Verified theories of atomic physics allow us to project time back to about the first second after the universe began.  Limitations in experimental and theoretical physics currently prevent us from confidently projecting back much further than that.

My first important point is that the universe had a beginning.  This is the consensus view in the science community.  If the universe had a beginning, then there has been a limited, finite amount of time for the universe to develop to where it is today.  That time limit is 13.7 billion years.  This point is important because it puts limitations on what a completely random process can produce compared to a rational process.  In other words, if 13.7 billion years is insufficient time for a random process and we know that some process produced a given result, then the existence of a result that is unlikely from a random process is evidence of a rational or a directed process.  The key assumption is that a rational process takes into consideration the laws of physics.

My second important point is that the Big Bang birth of the universe was orderly in the sense that it followed our known laws of physics.   It was not a chaotic explosion.  One significant piece of evidence that the creation was orderly is the extremely low entropy at the creation.  Entropy has traditionally been used as a measure of disorder: high entropy means high disorder.  The more modern explanation is that entropy measures energy dispersal.  Low entropy means concentrated energy and high entropy means dispersed energy.  We shall be using both interpretations, but I would like to point out that high energy concentrations call for our attention and amazement.  Lightning is an example of concentrated energy and we are justly attentive to its power.   Concentrated energy is unusual because of the second law of thermodynamics which states that in any natural process, energy tends to disperse: heat flows from the warmer object to the cooler object until thermal equilibrium is reached.

The primary elements of the Big Bang were hydrogen and helium in a ratio of approximately 75% hydrogen to 25% helium.  This is the ratio that would be expected from atomic physics for which we have very good experimental and observational data.  Elements heavier than helium like carbon and oxygen are created during the fusion of elements that takes place at the center of stars and during the explosion of large stars called supernovas.   The heavier elements that are essential for human life were fused in stars and spread into the universe from exploding stars; hence the expression that we are composed of “star dust.”

To give some idea of how low the entropy was at the creation, Roger Penrose has calculated the ratio of the energy dispersal at the beginning to the energy dispersal of the universe at its end.  That ratio gives an entropy of approximately 10123: that’s 1 followed by 123 zeroes.  Rather than explain Penrose’s math (which is based on the entropy of a massive black hole representing the entire universe), I would like to ask you to imagine the universe at its end, when all the stars have burned themselves out and all their heat and elements have been scattered uniformly throughout the universe.  That is complete energy dispersal.  At that point, the universe is at thermal equilibrium at a temperature near absolute zero.  The huge entropy calculated by Penrose represents the complete dispersal of energy compared to the incredible orderly concentration of energy at the beginning.

Stated another way, the beginning of the universe was very special because of the huge store of concentrated potential energy that was present in the 75% hydrogen and 25% helium that was created.  We could imagine another creation scenario where, instead of hydrogen and helium, we got iron or some random mixture of elements.  If the universe started out with iron, it would have no reserve of energy to burn in stars.  Almost any random mixture of elements would contain less energy for future use.  If there were no stars, there would be no life.

This discussion of entropy is typically the type of discussion one might have when one speaks of the universe being fine-tuned for life.  We can imagine the universe being created with just slightly different rules or values for certain constants so that life would not be possible.  There are about 20 different constants that need to have just the right values or we would have a very different universe, most likely one where life was not possible.  One way to visualize the complex dependencies present in the laws of physics is to look closely at the first 30 minutes of the creation.  The following description is based on Steven Weinberg’s, The First Three Minutes, along with other sources.

Somewhere around one second after creation, the universe is a very hot ‘soup’ of particles: protons, neutrons, electrons, positrons (anti-electrons), photons (particles of light) and neutrinos.  By this time, the protons and neutrons are those remaining after annihilation with corresponding anti-protons and anti-neutrons.  This slight excess (1 part in 1 billion) of protons and neutrons over their corresponding anti-particles is one of the big puzzles of the early universe. The remaining protons and neutrons are in thermal equilibrium with particles constantly undergoing atomic reactions such as protons changing into neutrons and vice versa.  Very energetic photons (particles of light) are constantly creating electrons and positrons which then annihilate each other creating another photon.  Protons and neutrons are beginning to come out of equilibrium and at that point neutrons comprise about 18% of the total number of neutrons plus protons.

As the universe cools, the density of protons with respect to neutrons is no longer governed by thermal equilibrium and the natural decay of neutrons into protons begins to dominate.  After the universe is about 10 seconds old, this decay is controlled by the Weak interaction (Beta decay), which causes the neutron to emit an electron and a neutrino, thereby converting into a positively charged proton.  Beta decay is a relatively slow process and the normal half-life of a free neutron (in this environment) is about 10 minutes.  That means that half of all free neutrons will convert to protons in about 10 minutes.  Once a neutron becomes bound to a proton, it becomes much more stable. But it is still too hot for protons and neutrons to bind together – that will begin to happen after the 3 minute mark.

After about 20 seconds, the temperature has dropped to the point where photons are no longer energetic enough to create electrons and positrons (anti-electrons).  There is a slight imbalance in the number of electrons and positrons with the electrons having a slight excess.  This is another huge puzzle for the early universe, because not only is there no explanation for the excess of electrons, but the excess of electrons is thought to exactly match the excess protons so that the entire universe is electrically neutral.  If the earth and the sun had an electrical charge imbalance of only one part in 1036, the electric repulsion between them would be greater than the force of gravity.

Once the creation of electron-positron pairs ceases, all pairs will annihilate each other except for the slight excess in electrons.  It is still too hot for any electrons to combine with atomic nuclei; that won’t happen for at least 300,000 years.

After about three minutes, the ratio of neutrons to protons has dropped to 1 neutron for each 7 protons (about 13%, down from 18%).  This ratio is critical for predicting the observed ratio of hydrogen to helium.  At this point the universe has cooled sufficiently for the formation of atomic nuclei.  The process begins with the formation of deuterium, an isotope of hydrogen which has one proton and one neutron.  Deuterium then acquires another neutron to become tritium or it acquires another proton to become helium-3.  This is a short intermediate step that leads quickly to the very stable natural element, helium (minus the electrons), which has 2 neutrons and 2 protons.

After about 20 minutes, the universe has expanded and cooled to the point where nuclear fusion can no longer take place.  The percentage of helium produced is frozen at about 25%, by weight.  For each 16 nucleus particles (14 protons plus 2 neutrons), 4 (2 neutrons and 2 protons) are needed to make one helium nucleus.  And 4 is 25% of 16.  But there is also some deuterium remaining plus a very small number of other light elements (for example, helium-3 and lithium-7).  The small amount of deuterium remaining is a very important confirmation of this early creation scenario, because deuterium cannot be easily created by any natural process.  It is consumed, but not created and therefore the amount of deuterium in very young stars that we can observe in the early universe is a good indication of the amount of deuterium left over after nucleosynthesis ended.

The accepted scenario for the Big Bang is well confirmed by observation.  The quantity of light elements produced by fusion during the first 30 minutes is confirmed by measurement of these elements in stars and in interstellar dust.  These predictions are also dependent on the number of photons in the early universe and this is confirmed by observation of the cosmic microwave background radiation (CMBR).

But there are also some very big mysteries associated with the Big Bang.  I’ve already mentioned the very small excess of particles over anti-particles and the fact that the excess electrons must match very closely the excess protons so that the universe is electrically neutral.  There is also the puzzle of “dark matter” and “dark energy” for which there is no generally accepted theoretical answer.

There is also another kind of puzzle: why did the various laws of physics produce results that are so consistent with the growth of the universe.  One example is the force of gravity.  Gravity is a very weak force compared with the electric force.  The electrical attraction between electron and proton in the hydrogen atom is about 1039 (1 followed by 39 zeroes) time stronger than the gravitational attraction.  The force of electromagnetism is governed by quantum theory and the force of gravity is understood by Einstein’s general theory of relativity.  These two theories have not been reconciled and yet the early universe expanded at just the right rate and cooled at just the right rate to produce just the right fuel (hydrogen and helium) for stars to burn even though stars would not ignite for another 300 million years!

Those who have pondered the incredible fine tuning associated with the laws of physics find it hard to escape the incredible awe inspired by the birth of the universe.  How did all these forces and particles, governed by laws that we still don’t completely understand, how did they work together to produce a universe so conducive to life?  Does the universe know something that we don’t yet know?  As you might expect, there is another point of view.

That other point of view is the multiverse theory.  The multiverse theory says that our universe is not the only universe and that each one was produced by random chance.  Therefore, there should be nothing surprising about our universe.  We are here to ask these questions because random chance has created a universe conducive to life.  That’s all.  The fact that physical theory and observation agree so much, that is a coincidence.  The abstract world of theory and the empirical world agree because human life has evolved to see the real world in ways that make sense to us.  There is no ontological necessity that the world has the attribute of making sense.

For me, that is a difficult argument to accept.  The strict discipline of mathematics does not appear to be the product of evolution, though there are cultural aspects:  nobody today is doing math with roman numerals.  But ii plus ii would still equal iv.  I take the perspective that the amazing correlation between the abstract world of mathematics and the empirical world is a remarkable confirmation that a rational force is at work in creation.

For those wanting to explore the multiverse theory (and an enjoyable read of historical developments), I would recommend Lawrence Krauss’ 2012 book, A Universe from Nothing: Why There is Something Rather than Nothing.  Krauss takes the path that the universe spontaneously burst into being from fluctuations in the quantum field and so leaves open the question of where did the quantum field come from.  Krauss’ path leads to multiple universes, each one created with random initial conditions, and that approach is very different from my approach which is based on the fact that the one universe we inhabit is the only one we can observe.  But his story of the Big Bang and his reasons for choosing his path are worth reading even if they differ from mine.

But even Krauss does not completely discount the possibility of a rational agent as a “first cause:”

In this regard, there is another important point to stress here. The apparent logical necessity of First Cause is a real issue for any universe that has a beginning. Therefore, on the basis of logic alone one cannot rule out such a deistic view of nature. But even in this case it is vital to realize that this deity bears no logical connection to the personal deities of the world’s great religions, in spite of the fact that it is often used to justify them. A deist who is compelled to search for some overarching intelligence to establish order in nature will not, in general, be driven to the personal God of the scriptures by the same logic.

Krauss’ observation about the difference between a rational first cause and the traditional deity of faith communities is important.  But I think that there is evidence that a rational power did not stop with creation, and that a rational power is currently active through life and consciousness.  I will continue to present such evidence in my next post.


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