  The two apparently distinct phenomena of dark energy (or late-time cosmic
acceleration) and quantum gravity dominate physics on extremely low, and
extremely high energies, but do not seem to have any apparent empirical
connection. Nevertheless, the two have a theoretical connection, through the
cosmological constant problem. I argue that the finite temperature quantum
gravitational corrections to black hole entropy yields a pressure for the
gravitational vacuum (or gravitational aether). Assuming that the relative
corrections are linear in horizon temperature (i.e. are suppressed by one power
of Planck energy), the pressure is comparable to that of dark energy for
astrophysical black holes. This implies that the observation of late-time
cosmic acceleration may have provided us with the first precision measurement
of quantum gravity, i.e. that of black hole entropy.
