But if the strength of dark energy really does diminish over cosmic time, the implications could run far wider and deeper. Wider, in the sense that it could provide fresh impetus for proponents of alternative cosmologies that change our understanding of the fate of the universe. And deeper, because it might even be telling us something profound about the deepest structure of space-time. “There certainly are very, very interesting possibilities for changing a lot of physics,” says Eric Linder, a physicist and cosmologist at the University of California, Berkeley.