In physical cosmology and astrophysics, dark energy is an unexplained type of energy that has a large effect on the cosmos. When was its existence first observed?

The earliest observable evidence for the existence of dark energy came from supernovae observations in 1998, which revealed that the universe does not expand at a steady pace, as Einstein had assumed. Rather, it expands at an accelerating rate.

Asked by Vasilii Kulev · Last updated 4 years ago · 1.7K views · SOURCE