Is dark energy static or dynamic?

While hypothesized dark energy can explain observations of the universe expanding at an accelerating rate, the specific properties of dark energy are still an enigma. Scientists think that dark energy could take one of two forms: a static cosmological constant that is homogenous over time and space, or a dynamical entity whose energy density changes in time and space. By examining data from a variety of experiments, scientists in a new study have developed a model that provides tantalizing hints that dark energy may be dynamic.