At the moment, there are only three explanations for this mystery: One is to say, "God did that," which explains nothing, even if it is true. The second is to invoke the Anthropic Principle's reasoning that if this weren't so, nobody would be here to notice it, so therefore we must see what we see. We'll examine a third option in a minute. No matter which logic one adopts, one has to come to terms with the fact that we are living in a very peculiar Cosmos.
Life-friendly values of physics are built into the universe like the cotton fabric woven into our currency. The Gravitational Constant is perhaps the most famous, but the Fine-Structure Constant is just as critical for life. Called Alpha, if it were just 1.1 or more of its present value, fusion would no longer occur in stars.
The Fine-Structure Constant gets so much scrutiny because the Big Bang created hydrogen and helium and almost nothing else. Life needs carbon and oxygen, but the latter is not so great a problem because oxygen is created in the cores of stars as an eventual product in nuclear fusion. Carbon is another story. So where did the carbon in our bodies come from? The answer involves those factories where all elements heavier than helium are manufactured: in the centers of suns.
When heavy suns explode into supernovae, their material is released into their environments, where they are taken up into the stuff that composes the next generation of stars and planets. Our sun is a third-generation star, and its surrounding planets, including all materials comprising the living organisms on Earth, are composed of this nicely enriched, third-generation, complex-material inventory.
For carbon, the key to its existence lies in an odd quirk within the nuclear fusion process that makes the stars shine. Now, the most common nuclear reaction happens when two extremely fast-moving atomic nuclei or protons collide and fuse to form a heavier element that is usually helium, but can be even heavier, especially as the star ages. Carbon should not be capable of being manufactured by this process, because its creation requires that three helium nuclei collide at the same identical microsecond. The likelihood of this happening, even in the frenzied interiors of stars, is minuscule.
It was Fred Hoyle who correctly figured out that something unusual and amazing must be at play vastly to increase the odds of this rare three-way collision and give the universe the abundant carbon found in every living creature. The trick here was a kind of "resonance," where disparate effects can come together to form something unexpected - the way the wind resonated with the structure of the Tacoma Narrows bridge, causing it to sway and collapse. Bingo: It turns out that carbon has a resonant state at just the correct energy to let stars create it in significant quantities. The carbon resonance, in turn, directly depends on the value of the Strong Force, which is what glues together each atomic nucleus out to the farthest villages of space-time.
If the Strong Force and gravity are so amazingly tweaked, we can't ignore the electromagnetic force that holds sway in the electrical and magnetic connections found in all atoms. Discussing it, the great theoretical physicist Richard Feynman said in his book, The Strange Theory of Light and Matter (Princeton University Press 1985), "It has been a mystery ever since it was discovered more than 50 years ago, and all good theoretical physicists put this number up on their wall and worry about it. Immediately you would like to know where this number for a coupling comes from. Nobody knows. It's one of the greatest damn mysteries of physics: a magic number that comes to us with no understanding by man. You might say the 'hand of God' wrote that number. We can measure this number very accurately, but we don't know what kind of dance to do on the computer to make this number come out, without putting it in secretly!"
It amounts to 1/137 when the units are filled in, and this constant of electromagnetism - another of the four fundamental forces - helps facilitate the existence of atoms and allows the entire visible universe to exist. Any small change in its value, and none of us is here.
Our third choice to explain "Goldilocks" is to allow that the universe only exists correlatively with conscious observers. Then no universe that didn't allow for life could possibly exist. This fits very neatly into quantum theory and Nobel laureate John Wheeler's participatory universe. Since, if indeed there ever was such a time that the Cosmos was in an undetermined probability state before the presence of observers (some probabilities - or most - not allowing for life), when observation began and the universe collapsed into a real state, it inevitably collapsed into a state that allowed for the observation that collapsed it. The mystery of the "Goldilocks" universe goes away.
Take your pick. Or try to come up with a better explanation. In any event, the standard textbook notion of a random billiard-ball Cosmos that could have had any forces that boast any range of values, but instead by chance alone has the oddly specific ones needed for life, looks impossible enough to seem downright silly.
Adapted from my new book Biocentrism, co-authored with Robert Lanza, MD.