The pressure inside the particles that make up each atom in the Universe could be greater than the pressure observed in the densest stars, according to new measurements.
Scientists at the Jefferson Lab in Virginia recently calculated the pressure inside the protons that constitute our atoms. And the result is pretty staggering: it would be higher than the pressure felt in a neutron star. “Neutron stars are among the densest objects we know in the Universe,” says Volker Burkert, lead author of the study. The researchers here estimated the pressure experienced by quarks — the particles that make up the atoms’ protons — at 100 decillions Pascal (a decillion is 1 followed by 33 zeros), which is about ten times higher than the pressure felt in the heart of a neutron star.
“We found an extremely high outward pressure at the center of the proton, and a much deeper inward pressure near the periphery of the proton,” says the researcher, who notes that the distribution of the pressure in the proton is dictated by the strong force (one of the four fundamental forces of nature) that binds three quarks together to form a proton. “We are providing a way to visualize the magnitude and distribution of the strong force inside the proton, opening a new window on nuclear and particle physics that can be explored in the future.” Why is it interesting to know more about the proton? Because without protons, there would be no atoms, so no matter, which means no life.
Moreover, the physicists still measure two different values for the radius of the proton, a frustrating incoherence. This research could, on the other hand, offer a new way of measuring the proton radius as a function of the pressure distribution inside the particle. More accurate experiments to measure other properties of the proton are on the horizon, which would reduce some of the uncertainty currently faced by researchers. But it is still worthwhile to appreciate the fact that it takes a lot of effort for nature to keep these little quarks together.