Makc,makc wrote:what is untestable is "parallel universe". if another universe is not parallel, it may therefore intersect our, and so prove its existance.
If the other universe has atleast a dimension that is common with our universe than it is not a parallel Universe. If this dimension is one of the recognized dimension, it could be found in near future. If the two universes are connected by hypothatical fifth dimesion (As example through blackhole-warm hole connection, energy string etc etc) than two such universes could have their own laws in their own (four?) dimensions with common dimension for energy loss from one to another universe.
It was also believed that the resultant rate of expansion of our universe is due to gravity from one universe affecting another.
All these are at hypothatical level. Nothing has been proved so far but, it doesn't mean it doesn't exist. Either us or our theories and math need further evolution.
Keep an open mind......