“There was a long history of speculation that in quantum gravity, unlike Einstein’s classical theory, it might be possible for the topology of spacetime to change.” -Edward Witten
General relativity makes very specific prediction for what the curvature of space should be at the event horizon of a black hole, and for the consequences to spacetime are for a mass accelerating outside, near and through it. However, a fully quantum theory of gravity is needed to understand what happens at or near a black hole’s singularity.
In some variations of quantum gravity, though, there are departures from Einstein’s theory that will extend farther out than the singularity itself, and these variations may be testable by LIGO. As more events come in, we can look for deviations from general relativity’s predictions, and if we find them, perhaps we’ll uncover the first evidence for gravitational physics beyond the scope of Einstein’s relativity after all.