Cosmic Coincidences

Image: Representation of a section
of DNA made by Richard Wheeler.

There are many things about the universe we live in that are just right for life as we know it to exist. Not only are there parameters that must have values that lie in a very narrow range, but there are also “coincidences” of seemingly unrelated phenomena that are crucial. One example is why some of the elements critical for life happen to be among the more abundant ones in the universe.

Our bodies, like most organic matter, are composed primarily of four elements: hydrogen, carbon, nitrogen and oxygen. The first, of course, is the simplest and most abundant element in the universe, but the remaining three are fairly special. All three are capable of forming multiple chemical bonds, and all are (unusually) capable of forming multiple bonds with the same partner atom. For example, elemental oxygen, O2 is a gas where two oxygen atoms share two chemical bonds. In contrast sulfur is a solid because, although it is in many ways chemically similar to oxygen and also forms two chemical bonds, it cannot form both of them with the same atom and therefore forms a solid network of atoms. The ability of these elements to form gaseous as well as liquid and solid compounds is critical for life, e.g. for respiration. Similarly, carbon dioxide is a gas because the carbon atom shares two of its four bonds with each oxygen atom, but silicon dioxide (a principle element of many rocks) cannot form double bonds. The unusually flexible atomic bonds of these elements, especially carbon, also allow them to a wide range of complex molecules that form the building blocks of life, such as sugars, proteins and DNA. The unusually flexible bonds of carbon, nitrogen and oxygen (C, N & O) give them special chemical properties such that it is difficult to conceive of life existing without them.

Fortunately for us, these three elements are among the more abundant in the universe. After hydrogen and helium (which composed the vast majority of the sun and the universe) they are the three most common types of atoms in our solar system and our galaxy. A remarkable thing is that C, N & O are far more abundant than elements before or after them on the periodic chart. Lithium, beryllium and boron before, and fluorine afterwards do not even make the top twenty five most common elements, and the only other element that comes close to C, N & O in abundance is chemically inert neon. The remaining elements in the top ten most common are iron, silicon, magnesium and sulfur, which are major components of Earth’s crust and core.

The reason for these elements abundance has to do with nuclear synthesis in stars. After the Big Bang, there was only hydrogen, a little helium, and trace amounts of lithium. Everything else has been produce in stars as they fuse hydrogen into helium other elements, making heavier elements and releasing energy in the process. In stars like our sun, this primarily happens by the direct route that is slowed by the weak nuclear force. However, in more massive stars a different path becomes possible that uses C, N & O as catalysts in what is known as the C-N-O cycle. This enables these massive stars to use up their hydrogen much faster, producing a lot of C, N & O in the process, and creating less stable stars that eventually explode in a supernova that blows much of the star’s matter into space and creates the heaviest elements, such as gold, lead and uranium. Thus our existence is in part the result of one or more stars exploding and seeding what became our solar system with their ashes.

Besides pointing out that not just anything will work as the building blocks for life and that one or more stars were sacrificed to enable our existence, I want to make the point out that the abundance of C, N & O is completely unrelated to their usefulness. The relative abundance of C, N & O has to do with their nuclear properties which in turn are based on the strong nuclear force and properties of neutrons and protons. The chemical properties, in turn, depend on the electrical force and the properties of electrons. There is no known fundamental physical reason why these two different processes should pick the same three elements.

I’ve gone on longer than I intended, so I’ll close with the observation that this is not the only one of seeming coincidences. Water, one of the most common compounds in our world, is also very unusual in its high ability to absorb heat, ability to dissolve ionic and non-ionic compounds, and that ice floats. For this reason, it is difficult to imagine life without the presence of water. These unique properties are a result of its unusual molecular structure resulting from electrical interactions and chemical bonding. Its high abundance on Earth and in the solar system stems that it is composed of the two most common chemically active elements in the solar system. Once again, nuclear processes give rise to the high abundance of something with unique chemical properties needed for life. This and the previous post may raise the question as to whether there is an explanation; I’d discuss several proposed ideas in my next post.

The Goldilocks Universe

As I pointed out in my last post, it seems to me that the very existence of the Universe demands an explanation that Science cannot provide. Natural science is fundamentally a description of the way the universe is and doesn't really address why it is one way and not another. A scientific explanation is at its heart a description of phenomena in terms of a more fundamental phenomenon. We say the apple falls because of gravity, which is an attraction between bodies that have mass, which might be further described in the way they affect space and time around them, or in terms of special particles or fields. Science can also tell us the many consequences, both obvious and subtle, were gravity to not exist, but ultimately, at the most fundamental level, it cannot tell us why our universe is constructed in a way that includes that which gives rise to gravity as opposed to one that doesn't. This is not because the science is incomplete, but because those questions belong to the realm of metaphysics, where we need philosophy or perhaps theology to answer them.

In addition to the curious fact that there is something rather than nothing, there is another curious fact that many things in our universe and world are just right for life. Just like Goldilocks found only one of several possible bowls of porridge to be just right, there are numerous fundamental entities and forces that are just right for a universe in which life could exist. Prime examples include the relative properties of different fundamental particles and the strengths of different fundamental forces which, if even slightly different, would result in a radically different and inhospitable universe.

One example involves protons and neutrons, the two particles of which the nucleus of all atoms are composed. While the known subatomic particles exhibit a large range of masses, somewhat unusually neutrons are almost exactly the same mass as protons, only about 0.1% heavier. This leads to the fact that an isolated neutron will eventually decay into a proton (though taking a much longer period than most subatomic particles) but neutrons are stable inside bonds that hold a nucleus together. If they were lighter than protons, protons would turn into neutrons, and no atoms would exist in the universe. If they were an additional 0.1%-0.2% percent heavier, they wouldn't be stable inside an atom and we would have a universe of only hydrogen. Even if just a little bit lighter-say only 0.05% heavier than protons-would give us a universe of massive thermonuclear bombs instead of stable stars. At that mass, neutrons could not decay into protons, since they also produce an electron in the process, and there would be roughly as many neutrons as protons in our universe. Besides size, the biggest difference between a hydrogen bomb and our sun is that the former contains lots of hydrogen that contains neutrons, which allows the nuclear reactions to happen very quickly, while the stars mostly consist of hydrogen that does not contain any neutrons. Thus if neutrons were just a tiny bit lighter, our sun and the rest of the stars would burn out quickly and be unstable in the process. In summary, of all the different masses a neutron could have, it lies within a very narrow range that makes it possible for ourselves and everything we know to exist.

Another example of the perfect balance of the universe is the strengths of the fundamental nuclear forces. These two are known as the strong and weak nuclear forces because by one way of measuring the strong one is about 1040 (ten thousand trillion trillion trillion) times stronger than the weak. Were the strong nuclear force only a few percent weaker, there would be no nuclear reactions in stars producing other elements because deuterium (a proton and neutron together which is the first step in the process) would not be stable. If it were a few percent stronger, regular hydrogen would become as explosive as that found in hydrogen bombs, as the strong force could bind two protons together without any neutrons. This is because the critical first step in nuclear fusion requires that the two forces work together to form deuterium out of two protons, which is really hard and therefore really slow due how weak the second force is. If it could be bypassed, or it were stronger, such 1/1039 the strength of the strong force, nuclear fusion would happen much faster, rendering most stars unstable. If on the other hand, it were even weaker, like 1/1041 the strength of the strong force, there would be little energy from the sun and few elements besides hydrogen.

These are but a few examples of situations were properties of fundamental particles and/or forces happen to lie in a narrow range that makes possible the universe that we know. There are others that involve gravity and the electrical force, the density of mater in the universe, the mass of neutrinos, and others. They are all situations where something is neither too strong nor too weak, neither too heavy nor too light, but are just right. These are also things for which we have no working theory as to why they have the strength or mass they do; it is conceivable that they could have had very different values, but we are fortunate that they have the specific values to allow the universe that we know to exist.

In my next few posts I will discuss more about some of the amazing balance that we find in the structure of the universe. These of course seem to me to be fingerprints that point to something more than material reality, but don't take my word for it yet.

Image: Test of hydrogen bomb "Mike".

A beginning must have a cause

In my previous post, I mentioned some of the evidence supporting the idea that our universe began about fourteen billion years ago in an unimaginable burst of energy that subsequently became all the matter and energy in the universe. The occurrence of this event known as the Big Bang is so well established that it undergrids pretty much every aspect of modern astronomy, as well as much of modern geology and biology, although not quite as directly. The evidence is strong enough that even some of the leaders of the Intelligent Design movement, including Phillip Johnson and William Dembski, accept an old Earth and old universe, even as they try to undermine evolutionary theory. When there are multiple pieces of evidence from disparate sources that all point to the same thing, it makes a strong case that thing is true.

Throughout our individual and corporate history, we observe that everything that began has a cause. A city has its founder(s), a child the coming together of its parents, a tsunami has its earthquake, and an automobile the company that made it. We would be incredulous with a court that stated that there was no agent that caused a crime, a doctor that told us that the cause of our symptoms was those very symptoms, or an archeologist that claimed Stonehenge was built by the rocks themselves. So when we state that the universe began in the Big Bang, we are implying that there is also something that caused it to begin, something that is other than the universe itself.

This, of course, raises questions about the nature of that cause. Either it, too, had a beginning and therefore a cause in a chain going back to time immortal, or it must be something that has no beginning, which could be referred to as the first cause. The second option is preferable not only from Occam’s Razor, but that the nature of our universe implies its cause exists outside of space and time as we know it. The most distant galaxies are receding from us at a rate that would violate Einstein’s theory of relativity if the universe was expanding into pre-existing space; that and other considerations point to that the expansion of the universe itself is creating space. The theory of relativity also reveals to us that time and space are closely entwined, so it is unclear if time and space as we know them even existed before the Big Bang. Thus, the universe’s cause probably exists outside of time and space as we understand them, which would again imply the cause had no beginning.

This leads to another conundrum. How could an eternal, beginningless cause cause something to begin at a specific time? An unchanging, impersonal force will always be doing the same thing, so a timeless cause would seem to imply a timeless effect. The only way an eternal cause could lead to an effect in time would be something about that cause change—like a decision made—but that change would have to come from within the cause itself. That would imply that this cause has at least some characteristics of a person—we are capable of deciding to do one thing or another without always having an outside cause. So it appears that the universe’s cause has at least certain aspects of personhood, namely the ability to freely make decisions, like “I am going to create a universe today.”

Thus the fact of the Big Bang implies there is something more than the physical universe. It implies that there is something that caused it to come into existence. It further implies that this something must be self-existent (not have a cause), immaterial (all mater was created in the Big Bang), eternal, outside of space and time, and having at least some characteristics of personhood, such as the ability to make decisions. In other words, the universe has a Creator.

Image: Hubble Deep Field image reveals a large number of distant galaxies. (NASA)

Thank God for the Big Bang

I thank God for the Big Bang. Seriously. After all, if there was no beginning of our universe, there would be no universe, no Sun, no Earth, no life and no people. But beyond providing for our existence, the Big Bang is one piece of evidence that points me to the Creator.

The evidence is quite strong that our universe exploded into existence in a cosmic fireball of unimaginable heat and density somewhere around fourteen billion years ago. There are multiple lines of evidence that support this. One is the recession of galaxies; based on the shifting of the wavelengths and the relative brightness of light coming from distant galaxies and supernovas, there is a clear pattern that the further away from us a galaxy is, the faster it is moving away from us. Second is the cosmic microwave background, a radio-wavelength signal that comes at us nearly uniformly from every direction in the sky. The best explanation on offer for that is “fossil” light from the early universe when atoms stated to form, that has had its wavelengths stretched to radio signal lengths by the expansion of the universe. Third is the relative abundance of elements in the primeval matter of the universe. There is still a lot of gas that has yet to be incorporated into stars or planets in our universe, which consists mostly of hydrogen, a little helium and traces of lithium. The relative abundances of these, which are consistent everywhere we can look, are best explained by a model in which the dense early universe past briefly through a phase in which it was cool enough for atomic nuclei to be stable but still hot and dense enough for some nuclear reactions to occur. Forth is the presence of heavier elements, such as carbon, iron and lead. These are not found in “pristine” matter in the universe, but rather are products of nuclear reactions in stars, with the heaviest elements like lead and gold being created in a supernova explosion when a massive star turns into a giant hydrogen bomb and blows the majority of its mass into surrounding space; once there some can be incorporated into new stellar systems, the way it appears to have happened for our solar system. With the even the shortest-lived stars having estimated lifetimes of several billion years, it took time to create all the iron and gold we use, but a much older universe would contain much more of that than what is observed. Coupled with observations from geology of sedimentation, crust renewal, fossils and various methods of radioactive dating, there are multiple lines of evidence that point to a beginning point in the distant past for the universe we live in.

It is these multiple lines of evidence, largely independent of each other but all pointing in the same direction, that gives us such strong confidence that the Big Bang is a fairly accurate description of what actually happened. Any one piece of evidence might be misinterpreted or could be explained by an alternative theory, but when taken together, a single theory that explains all these different observations is far more likely to be true than a set of unrelated, ad hoc theories that each just explain one observation. In the same way, I believe that there are quite a few different pieces of evidence that point to the existence of a God who created the universe and (surprisingly) is somehow involved in the affairs of ordinary people. There is no smoking gun or one piece that people have not already attempted to explain away, but put together they give me a high level of confidence that God is not a product of human imagination but a real being and the force behind the universe and that which is in it.

For many years I have read, listened and pondered about what science, scripture, and other lines of inquiry can tell us about the nature of the universe we live in. A synthesis has slowly formed in my mind, weaving together insights from diverse fields that I believe does them justice and gives me a more comprehensive view of the world we live in. But much of that has happened in isolation, and I hope this blog I am starting can be a forum to think about these issues more in community. If I am misleading myself or have misunderstood things, I need other people point that out. On the other hand, if I am right about some of these things, I think I have a moral obligation to share with others so that they can draw on any good insights I might actually have. I’d like to invite you to join me on this endeavor, following my blog as I post thoughts about once a week, making comments to keep me honest and asking questions if things are not clear. My desire is to write such that it is understandable and engaging for a wide range of areas of study and religious beliefs, which is more challenging but I believe ultimately more rewarding. Please keep that in mind as you interact with this blog.

Image: Artist's rendering of a supernova explosion, (c) NASA, retrieved from http://www.nasa.gov/images/content/175872main_sn2006gy_main_330.jpg