Nonlocal Gravity
  The analysis of measurements of accelerated observers in Minkowski spacetime
has led to the development of nonlocal special relativity theory. Inertia and
gravitation are intimately connected in accordance with the principle of
equivalence. We therefore seek a nonlocal generalization of the theory of
gravitation such that in the new theory the field equations are
integro-differential equations for the local gravitational field. We show that
it is possible to develop a nonlocal generalization of Einstein's theory of
gravitation via the introduction of a scalar "constitutive" kernel in the
teleparallel equivalent of general relativity. The resulting nonlocal theory is
essentially equivalent to Einstein's theory plus "dark matter". That is,
nonlocality simulates dark matter by introducing a new source term into general
relativity. In the linear approximation for the nonlocal modification of
Newtonian gravity, we recover the theoretical basis for the phenomenological
Tohline-Kuhn modified gravity approach to the explanation of the astrophysical
evidence for dark matter.
