  The recently discovered alignment of quasar polarizations on very large
scales could possibly explained by considering cosmic strings on a warped five
dimensional spacetime. Compact objects, such as cosmic strings, could have
tremendous mass in the bulk, while their warped manifestations in the brane can
be consistent with general relativity in 4D. The self-gravitating cosmic string
induces gravitational wavelike disturbances which could have effects felt on
the brane, i.e., the massive effective 4D modes (Kaluza-Klein modes) of the
perturbative 5D graviton. This effect is amplified by the time dependent part
of the warp factor. Due to this warp factor, disturbances don't fade away
during the expansion of the universe. From a non-linear perturbation analysis
it is found that the effective Einstein 4D equations on an axially symmetric
spacetime, contain a "back-reaction" term on the righthand side caused by the
projected 5D Weyl tensor and can act as a dark energy term. The propagation
equations to first order for the metric components and scalar-gauge fields
contain $\varphi$-dependent terms, so the approximate wave solutions are no
longer axially symmetric. The disturbances, amplified by the warp factor, can
possess extremal values for fixed polar angles. This could explain the two
preferred polarization vectors mod $(\varphi, 90^o)$.
