Why is our universe suited for stars, galaxies and life to evolve? For stars to create atoms needs the stability of galaxies that would fly apart without dark matter. We make energy by nuclear fission that breaks higher nuclei apart but stars make energy by nuclear fusion that merges nuclei, as when two Hydrogen atoms form Helium. This process requires neutrons that the weak force just so happens to let stars create from protons. The laws of physics did not allow nuclear fusion to create the carbon atoms needed for life until a “just right” energy resonance was found that did:
“The energy at which the carbon resonance occurs is determined by the interplay between the strong nuclear force and the electromagnetic force. If the strong force were slightly stronger or slightly weaker … the universe might very well be devoid of life and go unobserved.” (Davies, 2006)
The Goldilocks Effect is that our universe has an unreasonable number of parameters set “just right” for life, without which we couldn’t exist. Were these values set “just so” by a kind creator or did an impartial system spawn many universes and we just happen to be on the life-supporting one? Ananthaswamy (2012) gives one example in detail:
“Take, for instance, the neutron. It is 1.00137841870 times heavier than the proton, which is what allows it to decay into a proton, electron and neutrino—a process that determined the relative abundances of hydrogen and helium after the big bang and gave us a universe dominated by hydrogen. If the neutron-to-proton mass ratio were even slightly different, we would be living in a very different universe: one, perhaps, with far too much helium, in which stars would have burned out too quickly for life to evolve, or one in which protons decayed into neutrons rather than the other way around, leaving the universe without atoms. So, in fact, we wouldn’t be living here at all—we wouldn’t exist.”
The conclusion isn’t that the universe is designed for life, as if so, it would be a poor design because most of the universe is inhospitable to life. Yet it is true that the parameters of our universe are balanced on a “knife edge”, for as Susskind says:
“The great mystery is not why there is dark energy. The great mystery is why there is so little of it [10−122]… The fact that we are just on the knife edge of existence, [that] if dark energy were very much bigger we wouldn’t be here, that’s the mystery.”
Other “cosmic coincidences” are (from Barnes, 2012):
1. Strong force. If the strong force were slightly stronger or weaker by just 1% there would be no carbon or heavier elements anywhere in the universe.
2. Weak force. If the weak force was any weaker the hydrogen in the universe would be greatly decreased, starving stars of nuclear fuel and leaving the universe a cold and lifeless place.
3. Neutrons. If neutrons were slightly less massive the universe would be entirely protons and if lower by 1%, then all protons would decay into neutrons, and no atoms other than hydrogen, helium, lithium and beryllium could form.
4. Cosmic microwave background. This radiation has a slight anisotropy, roughly one part in 100,000, just enough to allow stars and galaxies to form. Any smaller and the early universe would have been too smooth for stars and galaxies to form and any larger and stable stars with planetary systems would have been extremely rare.
5. Cosmological constant. The positive and negative contributions to the vacuum energy density cancel to 120-digit accuracy, but the 121st digit makes our universe possible.
Since all the above and more apply, our “luck” is hard to explain. And it is the entire universe that is fine-tuned to evolve, not just some part of it, so one can’t conclude it is a “lucky accident” based on a sample of one. Unless of course there are many universes, hence the popularity of multiverse theory despite it being a scientifically worthless idea. But to conclude that there had to be many universes in order to make our universe an accident is not science. To be clear, the fine-tuning of our universe is based on evidence but the multiverse is based on no evidence at all. As O’Leary notes:
“The multiverse has only ever existed, so far as we know, in the mind of man. Its most promising research programs, string theory and early rapid cosmic inflation theory, have bounced along on enthusiasm alone, prompting ever more arcane speculations for which there may never be any possibility of evidence.” (O’Leary, 2017)
A recent variant is Smolin’s speculation that black holes spawn universes, based on an old idea suggested by Hawking in 1987, again with no evidence. Just because a black hole is a mathematical infinity doesn’t mean it can create a universe.
In quantum realism, the physical universe came from a pre-existing quantum reality, so every universal parameter was defined from the start by the nature of that reality. A processing model expects the many parameters of the standard model to reduce to the core properties of a processing network, such as the network refresh rate (the speed of light), the network density (Planck’s constant) and the rate the network is expanding (the cosmological constant). From these, simulations based on quantum reverse engineering could derive the other parameters.
In this view, if other “bubble universes” arose in the quantum bulk as ours did, they would have exactly the same laws of physics except the initial symmetry might break the anti-matter way. Each universe would then undergo a quantum evolution, just as ours has. In this view, our universe is as it is based on the quantum reality that preceded it and there is no benefit to speculate why. Its parameters were neither accidental nor chosen, so the universe is neither designed for life nor not designed so. It just did what it could given the original quantum reality. That a river is finely-tuned for crocodiles to live in doesn’t mean it was designed for them but that crocodiles evolved to live in rivers. In the same way our universe is finely-tuned for life because life evolved to fit what it was given. In quantum realism, the conditions for the evolution of the universe were established when it began.