God or Science?

The following sections are included:

• CONTENTS
• INTRODUCTION

The following sections are included:

• Cosmogonies
• A Brief History of the Big Bang Theory
• Summary: Key points

Today we are quite certain that our Universe originated 13.8 billion years ago and was very different from what it is today and is expanding in an accelerated way. If we suppose to reverse the expansion motion, as is done when rewinding a movie, what we would expect would be to see the galaxies reverse their motion and all begin to move towards one point. Going back in time, the Universe would become smaller and warmer, reaching temperatures so high that matter, as we know it today, did not exist. We would arrive at a point, when the Universe was 10^–35 m in size, the Planck era, in which the laws of known physics would no longer apply. At smaller scales we need a theory that still does not exist: quantum gravity which is a combination of the theory of gravity and Quantum Mechanics. Starting from Planck’s time, known physics allows us to describe the most important phases of the evolution of the universe. It is of fundamental importance to remember that in any case the discussions relating to the previous 10^–12 s period are essentially speculations, as we will see better in chapter 5. Now we will talk about it a bit.

The world around us seems to be a continuum, that is, objects can be divided indefinitely. Anaxander, Anaximenes, Empedocles had built up a special idea of an element that was based on the idea of the continuum. Thanks to Aristotle these ideas rose to the rank of philosophy. He imagined that the world under the moon was composed of four elements: earth, water, air and fire, while the Sun and the stars were composed of a fifth element: the ether. This misconception dominated Western culture for millennia. Atomist theory, supported by Leucippus and Democritus and their followers, had a completely different point of view. According to this theory matter is made up of non-divisible basic elements, hence the term atom: indivisible, into more elementary elements. The cosmos was made up of an empty and unlimited space within which the atoms moved continuously, in a casual motion, which combined to give rise to material bodies. Only after two thousand years, the ideas of the atomists were proved to be correct. Dalton’s atomic hypothesis led to the first atomic theory of matter. Several other scientists tried to order the elements into groups with similar characteristics. Dmitri Mendeleyev in 1869 proposed a periodic system of elements that showed the variation of the chemical-physical properties when the elements were ordered according to increasing values of the atomic number. However, in the twentieth century several scientists, such as Ernst Mach, considered it an abstruse question, with no possibility of being verified. In 1905, Einstein with the interpretation of Brownian motion indirectly showed the existence of atoms. Today the existence of atoms is no longer in doubt. They are characterized by different sizes depending on how many basic components (protons, neutrons, electrons) they contain. It took about a hundred years and a great deal of theoretical and experimental effort to arrive at the formulation of a complete theory describing the fundamental interactions and the particles associated with them, the so-called standard model of particles that describes all fundamental particles and interactions except gravity.

We know that the Universe began 13.8 billion years ago. The beginning is usually indicated by the term Big Bang and in the common imagination it was a great explosion. It is well known that the Big Bang was not this. For Jim Peebles, Nobel prize and one of the nowadays greatest cosmologists,

With the accelerators we have today we can go back to the first billionth of a second (10^–12 s), in which the universe is made up of a plasma of quarks, leptons and gluons. This quark soup called quark-gluon plasma was first observed at Brookhaven National Laboratory in 2002. Discussions about the Universe prior to this time are based on speculative ideas. Ideas such as GUT that occurred well before 10^–12 s are based on well understood, but in any case, speculative, physical concepts. If we then venture into the Planck era the situation is even worse because the physics to describe what happened in that era has not yet been formulated: we need to quantize gravity…

In “Exposition du systeme du monde” (Exposition of the system of the world), in 1796 Pierre Simon de Laplace elaborated (in parallel to Kant) the hypothesis of the origin of the solar system from a primitive nebula. He gave the text to Napoleon who after reading it asked him why God was not mentioned in the whole text. Laplace replied: Sire, I had no need of that hypothesis. Laplace’s conclusions were based on determinism, the idea that the phenomena that occur in the world are linked to each other by precise cause-effect relationships. In this way of seeing the world, which reigned until the 20th century, probability was excluded and everything could be rigorously described using mathematical and physical laws. The deterministic universe was strictly regulated by causality. Returning to Laplace, he was convinced that using Newton’s laws, knowing the initial conditions of the Universe, it was possible to predict every past and future state of the same. In his words

The following sections are included:

• The Control Panel of the Universe
• The Cosmological Constant and Life in Our Universe
• The Anthropic Principles
• The Anthropic Principle does not Work if there is no Multiverse
• Summary: Keynotes

It has been known for a long time that the Universe seems to be fit for life. If we consider the existence of only one universe, the coincidences in the constants of physics lead us to think that someone has chosen them so that life appears, that is, that there is a creator. Today this point of view has changed for many physicists and this is due to the emergence of the concept of the multiverse. Thanks to the concept of the multiverse, the very strange characteristic of the Universe of being “friendly” to life can be explained simply as a selection effect, without requiring the existence of god. As we have seen when talking about inflation, the theory of the multiverse tells us that the Universe, understood in the classical way, is only a tiny part of a much larger and more complex system: a set of an enormous number of universes, or if you want distinct regions, such as the bubble universes created by chaotic inflation. If these universes differ from each other, life will only be born in those regions or universes with conditions favorable to life. Introducing the multiverse, the answer to the old questions “why is there something rather than nothing?”, “Why do we exist?”, have a simple answer: we have won a sort of cosmic lottery and we do not need God to explain our existence. For this solution to be valid we need a particular multiverse, one in which the physical laws or at least the constants of physics change from one universe to another. There are several paths that lead to the multiverse, not all of which are useful for our purpose of explaining why we exist without resort to a creator.

The problem of the formation of the Universe and what existed before its origin has affected all cultures of all times, as evidenced by the multitude of cosmologies that have been invented over the centuries. The answer to the question of the origin of the cosmos have been linked for millennia to mysticism and religions. There are myriads of eschatologies, doctrines aimed at investigating the destiny of the individual, of mankind and of the universe. With the evolution of societies, more philosophical and rational arguments were sought. Today, as is well known, the most popular scientific theory is that of the Big Bang. However, this theory has problems describing what happened in the initial stages of the universe’s formation, from the initial time to Planck’s time, corresponding to 10^–43 s after the Big Bang. The model does not even explain what there was before the Big Bang and an answer that is often given to this question is that it makes no sense to ask what there was before the Big Bang since space and time originated with the Big Bang. That is, the modern point of view is not much ahead of the point of view of Saint Augustine that we described in section 1.2, namely that the world was not created in time but with time. In a cyclic universe this point of view is incorrect because before the Big Bang there was simply another universe like ours.

How did life begin? Where do we come from and who are we? These are the biggest questions we can ask ourselves and which certainly have always fascinated the human being. Giving an answer poses problems of formidable difficulty. A large number of scientists, in the last century, have attacked the problem from different angles, but no one has so far been able to solve it. Despite this, research has made significant progress and it is hoped in the future to be able to find a solution to the problem. From a general point of view, some answers can be given. The best known is that life was created by a deity. As we know, there are and have existed a large number of ideas on the origin of the world linked to divinities. In more recent times a more cryptic theory has appeared, the intelligent design that does not deny the reality of evolution, but argues that the extreme complexity of living beings can only be explained by the existence of an intelligence that has directed the evolution to follow the paths it has followed. The second, following the astrophysicist Fred Hoyle and his theory of the stationary universe, according to which the Universe is eternal, life would never have an origin, life would always exist. His collaborator Wickramasinghe also supported this thesis, and the idea that space was full of life (viruses, bacteria, etc.). With the discovery that the theory of the stationary universe was wrong, the idea that life has always existed also decayed. A third possibility is that life did not originate on Earth, but that it came from space. This is the theory of panspermia. Proponents of this theory are Svante Arrhenius, Fred Hoyle, Francis Crick, among many. According to Crick there would have been too little time for a terrestrial origin of life and according to him it was more likely that an extraterrestrial civilization would have spread life everywhere. This is the hypothesis of guided panspermia. The idea of panspermia, of course, only moves the problem of the birth of life, from our planet to another place, but does not solve it. Panspermia is a scientific theory, but it is considered less likely than the local origin of life, that is, on Earth. Today we still don’t know how things happened, but step by step we are getting closer to knowing how they could have happened. Despite the progress made in this area, the controversy still exists between the idea that life is the result of chance, according to the ideas of Jacques Monod, or of a necessity imposed by natural laws, as argued by Ilya Prigogine. The study of the origin of life is so complex that it requires interdisciplinary work. Nobel laureates in physics, chemistry and biology have dealt with and continue to deal with this complex and extraordinarily interesting problem.

From the arguments deriving from physics and cosmology we have seen that there is no evidence that science has eliminated God. Among other sciences, biology is the one in which a number of thinkers argue that it is the science that best of all highlights the unnecessary existence of God. It is necessary to discuss whether the previous affirmation corresponds to the truth.

In this book I have used the most current knowledge that physics, cosmology, and biology offer us to try to understand if this knowledge somehow gives indications that our universe and life were born by chance or if the case does not succeed to explain everything we observe. The basic question from which we started was: “has science killed God?”. With God we must not mean the personal god envisioned by religions, but an intelligent entity that was able to give the initial push to the origin of the universe and of life. A being who has created the laws that the universe follows and which have allowed life to form in at least one of its planets. The very existence of these laws, and their comprehensibility make us think that the universe is imbued with intelligence and that the idea of an initiating intelligence should not be discarded. Although there are laws that govern the universe, we only have a partial understanding of them. For example, we have a theory that describes the fundamental interactions that contains a series of constants whose values are not predicted by the theory, which must be added by hand and which remain outside our explanation. That theory provides three families for quarks and leptons while the matter that makes up the universe is made up only of the particles of a family. There is matter, namely dark matter, which is not predicted by that theory. We have a theory of space-time, but we don’t understand what space and time really are. In the history of science there have been tremendous advances, in a few hundred years, so we should be hopeful that the future will bring us more knowledge that can fill the gaps in the knowledge we have today. Unfortunately, as Heisenberg showed there are limits to knowledge in the microscopic, while Kurt Godel showed that there are properties of numbers that are beyond our capabilities and that the whole system of mathematics cannot prove its consistency. The theorems demonstrated by Godel place limits on our knowledge: we will not be able to know everything about our universe, since mathematics is fundamental to understand the laws of nature. In other words, it seems that nature reveals itself in some of its features, allows us to know it in part, but keeps us away from total knowledge. There are other areas of physics that remind us of our limitations on knowledge: catastrophe theory or deterministic chaos theory. A typical example of catastrophe are earthquakes produced by relative movements between tectonic plates. These move slowly until at a certain point the sum of all these small movements causes a sort of break. Despite the studies on disasters, the theory of disasters does not allow us to make predictions. Continuous processes are easily modeled with the equations of physics, but when non-linearities come into play, we can no longer make predictions. An extreme case of non-linearity is chaos. Most systems are non-linear. As Lorentz showed in the 1960s, it is enough to have a simple system with three degrees of freedom, such as a simple double pendulum, for it to be chaotic. Examples of chaotic systems is the atmosphere; liquids under certain conditions have turbulent and chaotic behaviors. Contrary to what Laplace thought, the solar system is also a chaotic system over extremely long periods. One of the characteristics of chaotic systems is the strong dependence on initial conditions. What does it mean? If we take the simple case of the double pendulum, and drop the extremity from 1 m, it will show a certain evolution over time, but if we drop it from 1.0000000000000000000000001 m, the evolution at some point will become different from the previous one…

The following section is included:

• INDEX