Imagine that our sun were magically and suddenly replaced by a black hole of the same mass (1 solar mass). what would happen to earth in its orbit? imagine that our sun were magically and suddenly replaced by a black hole of the same mass (1 solar mass). what would happen to earth in its orbit? nothing—earth's orbit would remain the same. earth would slowly spiral inward until it settled into an orbit about the size of mercury's current orbit. earth would orbit faster, but at the same distance. earth would almost instantly be sucked into oblivion in the black hole.