Succinctly, this explanation states that: if time travel is possible, then multiple versions of the future exist in parallel universes
~!~ BLACK HOLES - you've just solved BLACK HOLES.... observe ...
If its true that one can shift into an alternate universe, then it would hold that every single event at every moment also has a alternate universe. So many universes paralleling along may create a huge cosmic feedback loop which causes immense planetary vibrations which simultaneously can cancel out alternating universes causing a matter - anti matter like chain reaction which forces matter to collapse upon itself thus creating invisible BLACK HOLES.... sort like galaxy sized super whomping woofer speakers eating energy up.