Cosmologic philosophy: fine tuning, of carbon (Introduction)

by David Turell @, Monday, May 13, 2019, 17:05 (98 days ago) @ David Turell

A new study of the Hoyle prediction, as to how carbon formed:

"The Hoyle state plays a crucial role in the helium burning of stars that have reached the red giant stage. The close proximity of this state to the triple-alpha threshold is needed for the production of carbon, oxygen, and other elements necessary for life. We investigate whether this life-essential condition is robust or delicately fine-tuned by measuring its dependence on the fundamental constants of nature, specifically the light quark mass and the strength of the electromagnetic interaction. We show that there exist strong correlations between the alpha-particle binding energy and the various energies relevant to the triple-alpha process. We derive limits on the variation of these fundamental parameters from the requirement that sufficient amounts of carbon and oxygen be generated in stars.

Rob Shelton explains:

"Hoyle argued that there must be a secret path to Carbon, one that involved not the addition of protons but the triple collision of three helium atoms. But any collision that was strong enough to make the helium stick (overcome the Coulomb repulsion) had too much energy to keep them stuck together. What he needed was an energy resonance in the Carbon nucleus that converted He + He ->Be +He -> Carbon with no leftover energy that might tear the new nucleus apart. And he knew that this secret path had to be there or he wouldn’t exist. It took several years of pleading, but finally Willy Fowler did the measurement and found it just as Hoyle had predicted.


"Epelbaum et al., 2013 think that the earlier refutations were poorly done. Having just invented a highly accurate numerical technique, they propose to test it on the fine-tuning of Hoyle’s state. So they take Hoyle’s prediction and ask “Just how fine-tuned is this resonance?” Or restating the question, “Was Hoyle lucky, or is the universe truly fine-tuned for carbon life?”


"If Hoyle is correct that the universe is fine-tuned for life, then the independent measures will likewise be fine-tuned. Contrariwise, if we are just lucky, then only the “Hoyle state” is fine-tuned, but everything else would be “broadly” tuned.

"This paper grabs some other, unconstrained nuclear constants like the Coulomb repulsion strength and the “mass of the light quark” and tweaks them in a model to see whether it destroys the ability of the Hoyle state to make Carbon-12. If nothing much changes, then we were just lucky–if there’s a sharp peak, then it appears the universe is fine-tuned to make C-12.

"When they are all done, they find that 3 independent variables in nuclear physics all have to be correlated within 2%. If we crank up the Coulomb force, then we have to crank up the light quark mass or we lose our C-12 production.


"Well, it could mean that there are “hidden correlations” in nuclear physics that no one knew were there. Or it might mean that these three quantities have been assigned arbitrary values based on their outcome–which is to say–designed.

"How is this different from the usual “fine tuning” arguments made by, for example, Luke Barnes? Luke argues that each fine-tuning variable is independent of the others, so for example, if variable-(a) gives 1:100 and variable-(b) gives 1:10, the combined statistic is 1:1000. This argument is rather that (a) and (b) are correlated, so their combined statistic is not 1000, but say, 200. This could mean either that we’ve found an explicit requirement of the designer (making C-12), or we’ve found a hidden theoretical connection between (a) & (b). What do they report?

“'Beyond such relatively small changes [2%], the anthropic principle appears necessary at this time to explain the observed reaction rate of the triple-alpha process. In order to make more definitive statements about carbon and oxygen production for larger changes in the fundamental parameters, a more precise determination of A_s and A_t is needed from future lattice QCD simulations.'”

"So their conclusion is that previous debunking is wrong and the Hoyle state really is fine-tuned,"

Comment: Great example of fine tuning. Carbon is the key to life.

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