Transcript: As examples of fine tuning in nature, consider the strength of the nuclear forces that hold the atom and the nucleus together. If the weak nuclear force were much stronger than it is, the big bang would have cooked all the hydrogen into helium rather than just a fraction of it with the result that in the present day universe there could be no water and no long-lived stable stars. If the weak nuclear force had been much weaker, early neutrons would not decay into protons and there would be no hydrogen at all. The strong nuclear force that binds the atom’s nucleus, if it were only two percent stronger, no protons would have formed early in the universe. Diprotons would have formed instead. There would therefore have been no stable atoms, and stars with diprotons in them would have burned a billion times faster than stars in our universe. If the strong nuclear force had been five percent weaker, the deuteron would not be bound, and stellar fusion would have been impossible. What all this means is that if either of the nuclear forces had been slightly different, the universe would have been physically reasonable but not a place where long-lived stars, biology, or life would have been possible.