Could a planet really orbit close enough for 1-hour = 7-year time dilation?

The 1-hour-equals-7-years time dilation in Interstellar demands a planet orbiting within the innermost stable circular orbit of a black hole — impossible around a non-spinning one, but general relativity permits it if the black hole spins fast enough. Working through the real orbital mechanics, the authors find these calculations carry genuine astrophysical weight beyond the film: extreme spin changes where stable orbits can exist, which matters for real accreting black holes and gravitational wave sources.