The quintom scenario explains this phenomenon's equation of state, and this influences the cosmic   microwave background through the integrated Sachs-Wolfe effect. The coincidence problem asks  when this phenomenon began to affect the universe. In 1998, Adam Riess gathered 
The quintom scenario explains this phenomenon's equation of state, and this influences the cosmic   microwave background through the integrated Sachs-Wolfe effect. The coincidence problem asks  when this phenomenon began to affect the universe. In 1998, Adam Riess gathered the first evidence   of this phenomenon by showing that type Ia ["one A"] supernovae appeared fainter than predicted.  The cosmological constant has been reintroduced to account for the acceleration caused by this  phenomenon that accounts for two-thirds of all mass-energy. Name this form of energy named for  being difficult to observe directly.
The quintom scenario explains this phenomenon's equation of state, and this influences the cosmic   microwave background through the integrated Sachs-Wolfe effect.