User blog:Wheelsecond/Energy and speed limit for transition to Tier 2-C

The difference between 3-A and very low 2-C is that Tier 3-A characters can destroy the contents of a universe, whereas very low 2-C characters can destroy the actual spacetime of the universe. It seems like this becomes a matter of special abilities rather than just scale--how is it possible to destroy spacetime with raw energy?

Well, you could use black holes. From an outside point of view, a black hole's interior basically doesn't exist. The event horizon is called an event horizon for a reason; nothing that happens inside of it matters to the outside world. In the 'curved sheet' model of spacetime, a black hole is basically an actual hole. Anything approaching an event horizon will appear to get slower and slower, due to relativity, but never actually reach it.

Basically, it's not unreasonable to say that, in the inside of a black hole, spacetime has been destroyed as we know it.

So, if a black hole's event horizon radius were to cover the entire observable universe, it would basically destroy the entire universe, if we're assuming the observable portion of it to be the real deal as far as tiers are concerned. However, gravitational waves propagate at the speed of light, and the observable universe expands at that speed as well.

This can be waived in fiction, where universe-level beings could attack faster than light. If a universe-scale black hole's gravity waves are FTL, it will eventually catch up with the edge of the observable universe, though with how much it increases by then, the mass of the black hole will have to increase as well.

If the propagation is instant, the black hole needs to have about 2.5 * 1070 Joules of mass-energy for the event horizon to stop at the edge of the observable universe. This number doesn't get that much higher if the propagation isn't instant; is it's only 2xFTL, it's 5 * 1070 Joules of mass-energy, and 2.5 * 1071 Joules is it's 1.1xFTL.

This is interesting because it implies that a more-than-marginally FTL character that can output ~1071 Joules can destroy the spacetime of the observable universe by creating a black hole.

And that's our lower bound.

For reference, you can unbind all of the galaxies in the universe with about 1064 Joules. Unbinding galactic clusters and such will take more, though--probably no more than 1067. Which means that the difference between breaking the universe's contents and breaking the universe itself would be a 1,000x or 10,000x difference.

Of course, this all assumes physics isn't being totally ignored. Which it very well could be, with universal characters on the loose.