Gravitational confinement of photons and matter from Induced Matter   theory
  Using an Extended Scharzschild-Anti de Sitter (ESAdS) metric here introduced, where the noncompact extra dimension is time-like, we study the gravitational confinement of matter and photons from a 5D vacuum. The important result here obtained is that the photon trajectories (in general, massless particles) are periodic. They are confined to a radius $r\leq 2 m G/c^2$ by the gravitational field. Massive test particles are also gravitationally confined, but their trajectories are not periodic. 
Mauricio Bellini (IFIMAR, Mar del Plata University and CONICET)
gr-qc