Around the horizon of a Planck mass black hole there exists a region the depth of 1 Planck length where only light can orbit. All massive objects, that is particles with mass, will be unable to sustain such an orbit and fall into the black hole through this entropy interface. As the mass of a black hole increases the depth of the entropy interface will also increase. With the radius of the lightlike circular orbit being the boundary. With one proviso. This is the Schwarzschild solution and so non-rotating. Finding the dimensions of this entropy interface for the Kerr solution should be the aim of research.