  We review a novel and authentic way to quantize gravity. This novel approach
is based on the fact that Einstein gravity can be formulated in terms of a
symplectic geometry rather than a Riemannian geometry in the context of
emergent gravity. An essential step for emergent gravity is to realize the
equivalence principle, the most important property in the theory of gravity
(general relativity), from U(1) gauge theory on a symplectic or Poisson
manifold. Through the realization of the equivalence principle, which is an
intrinsic property in symplectic geometry known as the Darboux theorem or the
Moser lemma, one can understand how diffeomorphism symmetry arises from
noncommutative U(1) gauge theory; thus, gravity can emerge from the
noncommutative electromagnetism, which is also an interacting theory. As a
consequence, a background-independent quantum gravity in which the prior
existence of any spacetime structure is not a priori assumed but is defined by
using the fundamental ingredients in quantum gravity theory can be formulated.
This scheme for quantum gravity can be used to resolve many notorious problems
in theoretical physics, such as the cosmological constant problem, to
understand the nature of dark energy, and to explain why gravity is so weak
compared to other forces. In particular, it leads to a remarkable picture of
what matter is. A matter field, such as leptons and quarks, simply arises as a
stable localized geometry, which is a topological object in the defining
algebra (noncommutative $\star$-algebra) of quantum gravity.
