  We give a simple nonsupersymmetric example in which chronology protection
follows from unitarity and the AdS/CFT correspondence. We consider a ball of
homogeneous, rotating dust in global AdS3 whose backreaction produces a region
of Goedel space inside the ball. We solve the Israel matching conditions to
find the geometry outside of the dust ball and compute its quantum numbers in
the dual CFT. When the radius of the dust ball exceeds a certain critical
value, the spacetime will contain closed timelike curves. Our main observation
is that precisely when this critical radius is exceeded, a unitarity bound in
the dual CFT is violated, leading to a holographic argument for chronology
protection.
