From: http://en.wikipedia.org/wiki/General_relativity http://en.wikipedia.org/wiki/Schwarzschild_radius http://en.wikipedia.org/wiki/Two-body_problem_in_general_relativity http://en.wikipedia.org/wiki/Gravitational_wave Diffie black hole: 3.65*10^18 solar masses Meeker black hole: 21*10^9 solar masses Baker black hole: 5.066*10^7 solar masses BH = black hole SR = Schwarzschild Radius Baker BH SR = 1 AU = 8.3 light-minutes Meeker BH SR = 415 AU = 57.5 light-hours Diffie BH SR = 7.2*10^10 AU = 1,139,381 light-years Photon orbit radius = 3/2*SR Photon orbit period = 2*pi*(3/2*SR)/c = 3*pi*SR/c Baker BH photon orbit period = 1.3 hours Meeker BH photon orbit period = 22.6 days Diffie BH photon orbit period = 10,738,416 years Orbital lifetime from gravitational radiation Baker BH with Earth orbiting at 5*SR = 2.6*10^10 years Meeker BH with Earth orbiting at 5*SR = 4.5*10^15 years Diffie BH with Earth orbiting at 5*SR = 1.4*10^32 years Meeker BH with Baker BH orbiting at 5*SR = 265 years Diffie BH with Meeker BH orbiting at 5*SR = 2*10^16 years The actual lifetime is likely to be infinite, since the Earth will be torn apart by tidal forces and schmeared out like a ring of Saturn, at which point it will no longer generate a gravitational wave because it is rotationally symmetric. Gravitational wave radiated power Sun with Earth orbiting at 1 AU = 196 watts Sun with Earth orbiting at 5 SR = 2.1*10^37 watts Baker black hole with Earth orbiting at 5*SR = 8.2*10^21 watts Meeker black hole with Earth orbiting at 5*SR = 4.75*10^16 watts Diffie black hole with Earth orbiting at 5*SR = 1.6 watts