  There are many spacetime geometries in general relativity which contain
closed timelike curves. A layperson might say that retrograde time travel is
possible in such spacetimes. To date no one has discovered a spacetime geometry
which emulates what a layperson would describe as a time machine.
  The purpose of this paper is to propose such a space-time geometry. In our
geometry, a bubble of curvature travels along a closed trajectory. The inside
of the bubble is Rindler spacetime, and the exterior is Minkowski spacetime.
Accelerating observers inside of the bubble travel along closed timelike
curves. The walls of the bubble are generated with matter which violates the
classical energy conditions. We refer to such a bubble as a Traversable
Achronal Retrograde Domain In Spacetime.
