  We consider scattering in quantum gravity and derive long-range classical and
quantum contributions to the scattering of light-like bosons and fermions
(spin-0, spin-1/2, spin-1) from an external massive scalar field, such as the
Sun or a black hole. This is achieved by treating general relativity as an
effective field theory and identifying the non-analytic pieces of the one-loop
gravitational scattering amplitude. It is emphasized throughout the paper how
modern amplitude techniques, involving spinor-helicity variables, unitarity,
and squaring relations in gravity enable much simplified computations. We
directly verify, as predicted by general relativity, that all classical effects
in our computation are universal (in the context of matter type and
statistics). Using an eikonal procedure we confirm the post-Newtonian general
relativity correction for light-like bending around large stellar objects. We
also comment on treating effects from quantum hbar dependent terms using the
same eikonal method.
