  We propose a new probe to test the nature of gravity at various redshifts
through large-scale cosmological observations. We use our void catalog,
extracted from the Sloan Digital Sky Survey (SDSS, DR10), to trace the
distribution of matter along the lines of sight to SNe Ia that are selected
from the Union 2 catalog. We study the relation between SNe Ia luminosities and
convergence and also the peculiar velocities of the sources. We show that the
effects, on SNe Ia luminosities, of convergence and of peculiar velocities
predicted by the theory of general relativity and theories of modified
gravities are different and hence provide a new probe of gravity at various
redshifts. We show that the present sparse large-scale data does not allow us
to determine any statistically- significant deviation from the theory of
general relativity but future more comprehensive surveys should provide us with
means for such an exploration.
