Ah, the wonders of quantum chemistry

Tonight, I decided to complete my advanced physical chemistry problem set far ahead of Friday’s due date. One of the problems asked for a reason why nuclear fusion in stars is possible given that the hydrogen nuclei do not possess enough kinetic energy to overcome the coulombic repulsions of neighboring nuclei (thus preventing fusion). Classically, the law of conservation of energy would say that nuclear fusion within stars in not even possible, but we all know this to be true, so what is going on?

Well, in short, by confining the hydrogen nuclei in a well of sorts, the energies are quantized and the wavefunction solutions to the Schrödinger equation the of those nuclei give that there exists a probability that the nuclei will exist outside the well—where other nuclei live. (Think tunneling.) If two nuclei are close enough, then fusion occurs. Cool!