  Binary pulsars are excellent laboratories to test the building blocks of
Einstein's theory of General Relativity. One of these is Lorentz symmetry which
states that physical phenomena appear the same for all inertially moving
observers. We study the effect of violations of Lorentz symmetry in the orbital
evolution of binary pulsars and find that it induces a much more rapid decay of
the binary's orbital period due to the emission of dipolar radiation. The
absence of such behavior in recent observations allows us to place the most
stringent constraints on Lorentz violation in gravity, thus verifying one of
the cornerstones of Einstein's theory much more accurately than any previous
gravitational observation.
