Fine-tuning of the universe for life III

Part III: The case of carbon formation 

Life as we know it, is carbon-based. Thus, the production of carbon is crucial to all known forms of life. Astronomers know that carbon is produced from nuclear reactions that take place inside stars. However, by the mid-1990s scientists thought that the most plausible pathway to build heavier elements, such as carbon, was by incremental accretion (that is, adding one proton or neutron at a time to lighter elements, starting with hydrogen). But soon they realized that forming heavier elements that way requires passing through atomic structures with a total of 5 protons and neutrons, known to be unstable and whom nuclear physicists now called the 5-nucleon crevasse. This barrier results from the incredibly short half-lives, of about one in a trillionth of a trillionth (1/10^24) of a second, of this configuration. Therefore, carbon cannot form this way.

For this reason, English astronomer Fred Hoyle proposed in 1954 the formation of carbon by the fusion of beryllium-8 with an atom of helium-4. Though beryllium-8 atoms are also highly unstable, they have half-lives just longer than elements with 5 nucleons to make collision with a single helium-4 atom likely enough to provide a plausible pathway for building carbon. But, not without a price.

As it turns out, the total energy of the beryllium-8 and the helium-4 atoms exceeded the total energy of the carbon-12 atom, therefore, a higher-energy version of carbon-12 must exist, one with an excitation state having exactly 7.65 MeV more energy than the “ground energy state” for carbon-12. This is what is known as a resonance level. The carbon-12 resonance level, however, had to be just so or the whole process wouldn’t work! This higher-energy version of carbon-12 was in fact discovered in 1956 by nuclear physicist Willy Fowler at the Kellog Radiation Laboratory at Caltech, whom Hoyle himself convinced to undertake the task (see B2FH paper).

Hoyle’s discovery of the resonance level of carbon-12 having the exact value of 7.65 MeV has very important implications as many precise conditions must be met for its existence. The strength of gravitational attraction, for instance, is crucial since it affects, on the one hand, the kinetic energy associated with the beryllium-8  and the helium-4 atoms and their ability to combine to form carbon, and on the other hand, it determines whether stars would last long enough to form solar systems capable of sustaining life.  Moreover, the precise strength of 2 out of the 4 fundamental forces of physics, the strong nuclear force and the electromagnetic force, should be just so as to make carbon-based life possible on Earth, since the effects of these forces within these specific atoms differ (e.g., their effects are different on beryllium-8 than on helium-4). These effects, in turn, are related to the number and configuration of their elementary particles (protons and neutrons). 

Modern supercomputer calculations indicate that the electromagnetic force and the strong nuclear force must have precise strengths, within about 0.5-4 % of their current levels, to make carbon  production possible.

Much more striking, the masses of the elementary particles that formed protons and neutrons, the so-called light quarks, must have precise values to allow for the production of the elements, including carbon, essential for a life-friendly universe. The fine-tuning of the masses of the quarks is roughly 1 part in 10^21.  Therefore, Hoyle’s carbon-12 resonance discovery reinforces the claim of the fine-tuning of the universe for life adding further cumulative evidence to it (see Part I and Part II).

All this evidence brought Hoyle to conclude:

“A common-sense interpretation of the facts suggests that a super-intellect has monkeyed with physics, as well as with chemistry and biology, and that there are no blind forces worth speaking about in nature. The numbers one calculates from the facts seem to me so overwhelming as to put this conclusion almost beyond question.”

Post based on Stephen C. Meyer's Return to the God Hypothesis book, chapter 7, see resources.