26 - Wednesday

Interestingly, using Josh's modified Kruskal mapping with no modifications to map to Schwarzschild coords and straight back produces this:

This suggests that while a normal Kruskal diagram can be though of as identifying regions III and IV as the antipode of regions I and II, this modified Kruskal diagram treats the interior of a black hole  (region II) as the antipode of the parallel universe (region III).

 

 

We need to use the modified Kruskal coordinates, because only in these can we have trajectories crossing between region III and region I.