If gravitational waves role through space time, gravity distorts it etc what would it take to 'tear'it? Simply a black hole or other point singularity? Or does that even do it? Any amount of energy lead to a higher dimension (2d, 3d, 4d) tear?
I'm not a physicist so apologies for the imprecise question.
There is the concept of Penrose-Hawking "thunderbolts", where a naked singularity spreads out at the speed of light from an evaporating black hole, a strong motivation for cosmic censorship proposals. As noted in this question, there has not been that much work on them. They do not seem to happen in 2 dimensions.
A tear in spacetime is basically a singularity in general relativity, that is a point where parameters goes to infinity. In theory it is possible for naked singularities (that is not hidden in the center of a blackhole) to exist (Anders gave a nice link about one I didn't knew about), yet none was ever seen, leading to the "cosmic censorship" proposal.
Since infinity doesn't feel very physical, it really means general relativity is wrong at this scale (and the singularities are not the only problem).
That's why we need a quantum theory of gravitation, as long as we only have general relativity we cannot modelize properly what is happening, because we will really do maths and not physics.
