  The topology of extra dimensions can break global Lorentz invariance,singling
out a globally preferred frame even in flat spacetime. Through experiments that
probe global topology, an observer can determine her state of motion with
respect to the preferred frame. This scenario is realized if we live on a brane
universe moving through a flat space with compact extra dimensions. We identify
three experimental effects due to the motion of our universe that one could
potentially detect using gravitational probes. One of these relates to the
peculiar properties of the twin paradox in multiply-connected spacetimes.
Another relies on the fact that the Kaluza-Klein modes of any bulk field are
sensitive to boundary conditions. A third concerns the modification to the
Newtonian potential on a moving brane. Remarkably, we find that even small
extra dimensions are detectable by brane observers if the brane is moving
sufficiently fast.
