The Pressure Holding You and All the Matter in Universe Together Measured for the First Time

The pressure in the middle of a proton is about 10 times higher than in a neutron star.  They call it the “strong force.”

The quark structure of the proton. There are two up quarks in it and one down quark. The strong force is mediated by gluons (wavey). The strong force has three types of charges, the so-called red, green and the blue. Note that the choice of green for the down quark is arbitrary; the “color charge” is thought of as circulating among the three quarks

Credit: Jacek rybak  / Wikimedia Commons

Researchers determined the pressure distribution inside the proton. They made the first measurement of a mechanical property of a subatomic particle. The team found that the proton’s building blocks, quarks, are subjected to an astounding pressure of 100 decillion Pascal (10 to the 35th) near the center of a proton. How much pressure? It’s about 10 times greater than the pressure in the heart of a neutron star.

The Continuous Electron Beam Accelerator Facility Large Acceptance Spectrometer in Jefferson Lab’s Experimental Hall B made the measurements that scientists used to tease out the proton’s internal pressure.

Credit: Jefferson Lab

The Impact

The result gives incredible insight into the distribution of the strong force inside the proton. The strong force holds the proton together. On top of that, the success of the experimental technique used opens the door for pioneering explorations of other mechanical properties of the proton.

Summary

Inside every proton in every atom in the universe is a pressure cooker environment that surpasses the atom-crushing heart of a neutron star. That’s according to the first measurement of a mechanical property of subatomic particles, the pressure distribution inside the proton, which was carried out by nuclear physicists at Jefferson Lab. Once thought impossible to obtain, this measurement is the result of a clever pairing of two theoretical frameworks with existing data. The first framework is the generalized parton distribution (GPD) that scientists use to create a 3D image of the proton’s structure as probed by the electromagnetic force.