During the late 1800’s, James Clerk Maxwell and Ludwig Boltzmann developed a differential equation that predicted how gaseous material distributes itself in space and how it reacts to changes in things like temperature, pressure or velocity. The only problem: for 140 years, solutions to the equation could only be found for gases that were perfect equilibrium. Enter Philip Gressman and Robert Strain of the University of Pennsylvania. Using recently developed mathematical techniques, they were able to describe solutions to the equation under any conditions. As this article in the Time of India notes, now it’s possible to “describe the location of gas molecules probabilistically and predict the likelihood that a molecule will reside at any particular location and have a particular momentum at any given time in the future.”