(Long) quote for the day: ...Our universe does seem singularly congenial as a home for intelligent life. L.J. Henderson's Fitness of the Environment extolled the remarkable life-enhancing properties of water, as well as pointing out the unique properties of the carbon atom, including the fact that carbon can bond with itself in a vastly larger number of combinations than any other atom. It is this wonderful property that makes complex organic chemistry possible.
Of course, these unique properties would have been little avail in fostering life, had it not been for the substantial abundance of oxygen and carbon. But since hydrogen and oxygen rank first and third, respectively, in cosmic abundance, water is guaranteed to be present throughout the universe, and carbon comes in fourth in order of cosmic abundance. If we were allowed to think of God in anthropomorphic terms, we would say, "Good planning!" Curiously enough, neither oxygen nor carbon emerged in the first three minutes of the Big Bang. At first glance, this might be labeled God's Goof. That's how the physicist George Gamow felt when he discovered the flaw in the nature of the light elements that prevented the heavier elements from forming. In the first minute of the Big Bang, energetic photons were transformed into protons, which fused into deuterium (nuclear particles of mass two), tritium (nuclear particles of mass three), and alpha particles (which would serve as mass-four nuclei of helium atoms). But there was no stable mass five, so at that point the fusion process stopped, well short of the twelve needed for carbon or the sixteen for oxygen...
...But far from being a design flaw in our universe, the absence of mass five seems essential to our existence. The lack of a stable mass five means that the element-building in the stars takes place as a two-step process: first, hydrogen is converted to helium, in the hot nuclear cauldrons at the cores of the stars; and then, once helium is abundant, it is built up into heavier atoms, in a second process. Because helium has a mass of four units, the fusion of two or three or four helium nuclei results in atoms of mass eight or twelve (carbon) or sixteen (oxygen), thus skipping over the unstable mass five. This second process requires a much higher temperature in the stellar interiors, one that is not reached until much of the hydrogen fuel has been exhausted--in the case of a star like the sun, only after about ten billion years. This guarantees a long, steady lifetime for sunlike stars. It is of course this tedious process that provides the stable solar environment in which the evolutionary biological sequences can work themselves out.
If mass five was not absent, that could not happen. Suppose that mass five were stable. Then, in the opening minutes of the universe, characterized by the overwhelming abundance of protons (each with a mass of one unit), atom-building could have taken place as mass increased by steps of one, right up the nuclear ladder toward iron. This would have left no special abundance of carbon (mass twelve) or oxygen (mass sixteen) , two essential building blocks of life...What at first glance appeared to be God's mistake turn out to be one of the Creator's most ingenious triumphs. (pp. 52-56 in God's Universe by Owen Gingerich, Professor of Astronomy and History of Science, Harvard University).