Physicists calculate proton’s pressure distribution for first time
Neutron stars are among the densest-known objects in the universe, withstanding pressures so great that one teaspoon of a star’s material would equal about 15 times the weight of the moon. Yet as it turns out, protons — the fundamental particles that make up most of the visible matter in the universe — contain even higher pressures. For the first time, MIT physicists have calculated a proton’s pressure distribution, and found that the particle contains a highly pressurized core that, at its most intense point, is generating greater pressures than are found inside a neutron star. This core pushes out from the proton’s center, while the surrounding region pushes inward. (Imagine a baseball attempting to expand inside a soccer ball that is collapsing.) The competing pressures act to stabilize the proton’s overall structure. The physicists’ results, published today in Physical Review Letters, represent the first time that scientists have calculated a proton’s pressure...