Fine tuning argument for the existence of God: Appearance of heavy elements in the Universe and tuning the fundamental forces of our universe

Appearance of heavy elements in the Universe

Heavy elements

98% of visible matter is made up of hydrogen and helium. All the other elements (heavy elements: carbon, iron, oxygen in particular which are the constituents of organic matter and therefore of human beings) represent only the remaining 2%. According to the Big Bang theory, only hydrogen and helium formed during the Big Bang and all other elements formed in stars over a period of billions of years. This realization led Hubert Reeves to say that we are “stardust”. According to the proponents of the anthropic principle, the fact that living organisms and in particular man are made of the rarest matter that exists in the universe tends to prove that this is the finality of the cosmic project.

Carbon

In its evolved version, the weak anthropic principle dates back to an article by Robert Dicke from 19618. In this article, Dicke points out that the appearance of life, or more generally of any complex biological structure, requires the presence of carbon, and that this seems to be the fruit of several favorable coincidences.

It was known at the time that carbon could not be produced during primordial nucleosynthesis, at the time of the Big Bang, but had to be synthesized within stars (stellar nucleosynthesis). However, even within stars, carbon is difficult to synthesize. The reason for this is that the two constituents present in quantity in a star at the time of its formation are hydrogen and helium, and there is no stable atomic nucleus produced from a collision between a nucleus of hydrogen and a helium nucleus or between two helium nuclei. Synthesizing heavier elements actually requires a collision between three helium nuclei. The mass energy of three helium nuclei together is, however, greater than that of a carbon nucleus. The synthesis of such a nucleus is thus disadvantaged. It turns out, however, that it is allowed thanks to the fact that there is an excited state of the carbon nucleus whose total energy (including the mass energy of the nucleus) is equal to that of the three helium nuclei. It is this coincidence, resulting a priori from chance, which allows the production of elements heavier than helium in the stars and consequently life. Moreover, the existence of such an excited state for carbon had been envisaged as early as 1953 by Fred Hoyle on the basis of these same observations and discovered immediately afterwards.

It was Fred Hoyle, to whom we owed the expression, initially pejorative, Big Bang, who introduced on this occasion a new expression which will know the success: “fine tuning of the universal constants”.

This point of view is not accepted by all researchers, as very diverse experiments on different types of universes suggest that emergence phenomena can also occur. Fred Adams, of the University of Ann Arbor (Michigan), for example, estimates that objects functionally comparable to the “stars” of our universe could occur in nearly a quarter of the universes conceivable to us by varying three parameters fundamental physics, including the gravitational constant G and the fine structure constant α.

Tuning the fundamental forces of our universe

Four fundamental forces govern our universe: the gravitational force, the strong force, the electromagnetic force and the weak force. Some authors think that if these four forces had been proportionally different, they would have produced phenomena incompatible with life.

Ratio of electromagnetic and gravitational forces

According to Hugh Ross, taken up by many authors, the ratio of electromagnetic and gravitational force is finely adjusted to within 10^-40.

According to this author, if the gravitational force had been less strong, there would have been no star less than 1,4 M_E and the life of stars would have been too short and too irregular to allow the appearance of life.

If the gravitational force had been stronger, there would have been no stars larger than 0,8 M_E and no heavy elements, essential for life, would have been produced.

Other forces

If the strong nuclear force had been slightly less strong, many elements would have been radioactive and unsuitable for biochemistry, the less energetic nuclear reactions would have greatly reduced the lifespan of the stars. Even less strong, and the only element that would have existed would have been hydrogen, eliminating all possible biochemistry; the stars would then have immediately collapsed into white dwarfs, or neutron stars, or black holes as soon as they condensed.

If the strong nuclear force had been slightly stronger, there would have been no hydrogen, it would have been consumed during primordial nucleosynthesis into helium (or heavier elements); and the stars would have no main sequence, they would quickly collapse as soon as they condense.

If the nuclear and electromagnetic forces had not had their respective values, they could not have generated the nuclear resonance of beryllium, carbon and oxygen and the production of the elements necessary for life based on these atoms.

(Includes texts from Wikipedia translated and adapted by Nicolae Sfetcu)