Thesis Repulsion Potential

Jorge Cham is brilliant.

Follow the link above to his latest cartoon at PHD Comics. Click to the previous comic to see the setup.

For those of you who don't know this, which might be everyone reading this blog, the potential shown in that cartoon is typical of the attractive force that holds protons and neutrons in the atomic nucleus. The nuclear force is short range and weakly attractive, but there is a very large repulsion at short distances that arises, essentially, from the Pauli exclusion principle acting between the quarks that make up the proton and neutron.

That repulsion sets the size of neutron stars.