 When one imagines these constants being different, one discovers that in fact the number of observable universes, that is to say, universes capable of supporting intelligent life, is very small. Just a slight variation in any one of these values would render life impossible. For example, if the strong force (as) were increased as much as 1%, nuclear resonance levels would be so altered that almost all carbon would be burned into oxygen; an increase of 2% would preclude formation of protons out of quarks, preventing the existence of atoms. Furthermore, weakening the strong force by as much as 5% would unbind deuteron, which is essential to stellar nucleosynthesis, leading to a universe composed only of hydrogen. It has been estimated that the strong force must be within 0.8 and 1.2 its actual strength or all elements of atomic weight greater than four would not have formed. Or again, if the weak force had been appreciably stronger, then the Big Bang’s nuclear burning would have proceeded past helium to iron, making fusion-powered stars impossible. But if it had been much weaker, then we should have had a universe entirely of helium. Or again, if gravitation aG had been a little greater, all stars would have been red dwarfs, which are too cold to support life-bearing planets. If it had been a little smaller, the universe would have been composed exclusively of blue giants, which burn too briefly for life to develop. This gives us reason to believe that there is an intelligent designer who fine-tuned the universe as we actually find it.