  The long-distance effective field theory of our Universe--the Standard Model
coupled to gravity--has a unique 4D vacuum, but we show that it also has a
landscape of lower-dimensional vacua, with the potential for moduli arising
from vacuum and Casimir energies. For minimal Majorana neutrino masses, we find
a near-continuous infinity of AdS3xS1 vacua, with circumference ~20 microns and
AdS3 length 4x10^25 m. By AdS/CFT, there is a CFT2 of central charge c~10^90
which contains the Standard Model (and beyond) coupled to quantum gravity in
this vacuum. Physics in these vacua is the same as in ours for energies between
10^-1 eV and 10^48 GeV, so this CFT2 also describes all the physics of our
vacuum in this energy range. We show that it is possible to realize
quantum-stabilized AdS vacua as near-horizon regions of new kinds of quantum
extremal black objects in the higher-dimensional space--near critical black
strings in 4D, near-critical black holes in 3D. The violation of the
null-energy condition by the Casimir energy is crucial for these horizons to
exist, as has already been realized for analogous non-extremal 3D black holes
by Emparan, Fabbri and Kaloper. The new extremal 3D black holes are
particularly interesting--they are (meta)stable with an entropy independent of
hbar and G_N, so a microscopic counting of the entropy may be possible in the
G_N->0 limit. Our results suggest that it should be possible to realize the
larger landscape of AdS vacua in string theory as near-horizon geometries of
new extremal black brane solutions.
