  General Relativity receives quantum corrections relevant at macroscopic
distance scales and near event horizons. These arise from the conformal scalar
degrees of freedom in the extended effective field theory of gravity generated
by the trace anomaly of massless quantum fields in curved space. The origin of
these conformal scalar degrees of freedom as massless poles in two-particle
intermediate states of anomalous amplitudes in flat space is exposed. At event
horizons the conformal anomaly scalar degrees of freedom can have
macroscopically large effects on the geometry, potentially removing the
classical event horizon of black hole and cosmological spacetimes, replacing
them with a quantum boundary layer where the effective value of the
gravitational vacuum energy density can change. In the effective theory, the
cosmological term becomes a dynamical condensate, whose value depends upon
boundary conditions near the horizon. In the conformal phase where the anomaly
induced fluctutations dominate, and the condensate dissolves, the effective
cosmological "constant" is a running coupling which has an infrared stable
fixed point at zero. By taking a positive value in the interior of a fully
collapsed star, the effective cosmological term removes any singularity,
replacing it with a smooth dark energy interior. The resulting gravitational
condensate star configuration resolves all black hole paradoxes, and provides a
testable alternative to black holes as the final state of complete
gravitational collapse. The observed dark energy of our universe likewise may
be a macroscopic finite size effect whose value depends not on microphysics but
on the cosmological horizon scale.
