The article presents substantiation of the principle of physical reality of imaginary numbers and explanation of their physical nature. It is shown that imaginary numbers in relativistic formulae of SRT are indicative of presence in the physical world we live in of other invisible parallel universes in addition to our universe. Therefore, the Multiverse containing them is referred to as hidden. It is shown that the phenomenon of dark matter and dark energy is explained by existence of plenty of mutually invisible parallel universes in the Multiverse. And, on the other hand, the phenomenon of dark matter and dark energy is an experimental proof of existence of the hidden Multiverse. Reasonableness of the proposed hypothesis is confirmed by observation data obtained from WMAP and Planck spacecrafts.

multiverse, imaginary numbers, special theory of relativity, dark matter, dark energy, dark dimensions