If we want to learn anything about the far future of the cosmos, we’d better address the giant invisible ever-expanding killer elephant in the room: dark energy. When the accelerated expansion of the universe was discovered in 1998, the new paradigm placed us squarely in the path of a dark-energy-dominated future: one in which the cosmos gets progressively emptier, colder, and darker until all structure decays and we reach the ultimate Heat Death. But this is just an extrapolation, one that’s predicated on dark energy being an unchanging cosmological constant. As we’ve seen, if whatever is
...more
