The properties of this phenomenon, which was named by Michael Turner, are described in one of the Friedmann equations, where it is modified by a scale factor.  
A recent paper used a Zeldovich-like non-perturbative approach to improve on the Chaplygin gas model of it. The properties of this phenomenon, which was named by Michael Turner, are described in one of the Friedmann equations, where it is modified by a scale factor.  One form of it appears in the Robertson-Walker metric, and in one model, it is derived from a dynamic scalar field, known as quintessence. Much of the evidence for it is from Type Ia supernovae, while the constant density version is encompassed by the cosmological constant. For 10 points, identify this substance comprising 75% of the cosmos, a force that acts to accelerate the rate of expansion of the universe.
A recent paper used a Zeldovich-like non-perturbative approach to improve on the Chaplygin gas model of it.
dark energy