Researchers at Stanford University observed a potential new black hole, comprising a unique signature that could help determine the mass and rotation rate of such objects with greater accuracy. The observations, made with a Rossi x-ray timing explorer satellite, showed a 67-Hz peak in the object's power spectrum, which is consistent with predictions made by the university's astrophysics group three years ago. The group had said that the powerful gravity produced by a massive black hole causes vibrations in surrounding gases that, in turn, cause detectable changes in radiation.