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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.

Qmechanic
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Dan Ward
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2 Answers2

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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.

Anders Sandberg
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  • black holes above $10^{32}$ kg can become charged enough to reach extremality and be stable against Schwinger decay. There is no known mechanism for those black holes to lose charge and stay away from extremality – lurscher Jul 23 '18 at 12:31
  • Thanks a lot! I'll explore these further. If I'm understanding correctly then we seem to be ok with 1d (singularity passing through time) and theoretically 2d (1+1) but no spacial surfaces or higher. Or am I missing something about time and singularities which removed them from that plane altogether? – Dan Ward Jul 23 '18 at 14:37
  • @lurscher - Why would they be stable against Schwinger decay if they are that massive? – Anders Sandberg Jul 23 '18 at 14:47
  • https://physics.stackexchange.com/q/47148/955 – lurscher Jul 23 '18 at 16:04
  • Following from the above the question becomes 'why not'? I appreciate that the strictly mathematical best known answers are linked above but at the end of the day if spacetime is a 'thing' that I'm encouraged to think of like a 4d volume I'm pretty surprised that the intuition that a role can be expanded to a tear is wrong. How should I think of this seemingly omnipotent material? – Dan Ward Jul 23 '18 at 23:25
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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.

kirinyaga
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