Is there a real chance that there is a multiverse?

[Alex K]

Yes, the problem is that Energy, as we learn the concept in school or even college, is not conserved contrary to popular opinion, because of cosmic expansion. A photon travelling from A to B gets redshifted and obviously loses energy. One can rescue energy as a conserved quantity if one assigns an energy to space itself. It then turns out that the energy of the photon, and of space as a whole, and the spacetime ripples the photon causes due to its gravity, taken together, can be considered conserved. If you then add up the energy of the matter and radiation and dark energy in a flat expanding universe+plus the energy assigned to spacetime itself, you can get zero, i.e. this gives the compelling picture that all energy of the contents of space is borrowed from spacetime itseld, which carries negative energy due to its expansion.