AMA | September 2024

1107.618 - 1129.206 Sean Carroll

We don't know exactly what either one of these things are, but in the case of dark energy, the thing that makes the universe accelerate, we have an overwhelmingly plausible candidate, namely Einstein's cosmological constant. And the cosmological constant is the least likely least intricate thing you can imagine. It's literally just one number. It is the energy density of empty space.