Largest supernova dataset hints dark energy may be changing over time

It took about 50 exploding stars to upend cosmology. Researchers mapped and measured light from Type Ia supernovae, the dramatic explosion of a particular kind of white dwarf. In 1998, they announced their surprising results: Instead of slowing down or staying constant, our universe was expanding faster and faster. The discovery of "dark energy," the unknown ingredient driving the accelerated expansion, was awarded a Nobel Prize.