Dark energy: Could the mysterious force we think of as constant actually vary over cosmic time?

Oct 10, 2024

,As I finished my Ph.D. in 1992, the universe was full of mystery—we didn't even know exactly what it is made of. One could argue that cosmologists had made little progress in our understanding of these basic facts since the discovery of the cosmic microwave background (CMB), the afterglow of the Big Bang, in the 1960s.