I think the Multiverse is much stranger than we imagine. Many of the top Theoretical Scientists now believe in an unlimited number of Dimensions. These Alternate and Multi Dimensions come, Consensually via modern Scientific thought, in one of 4 types. I won’t venture too deeply into the 4 primary different types, however, suffice it to say we may have parallel lives (Parallel Existence) or/and we may have other weird Dimensions flowing through where you are sitting right now. There may be Higher Vibratory Dimensions and Fractured “Reality” Dimensions. There may even be several types of Alternate Reality / Dimensions that we haven’t even theorized yet. I find it very Exciting that we may actually have an unlimited number of Alternate Lives, and that other Inhabitants may be Dimensionally “Visiting” right now. Some of the best works on the subject are by Dr. Michio Kaku, and on a more Paranormal vista - works by John A. Keel (especially: The Mothman Prophecies) and Jacques Vallée. Vallee's UFO classic, Messengers of Deception is quite an interesting read.
I do wish to share a thought that flows through that mess I call a mind now and then: Imagine a technologically advanced Alien Civilization that was 500 years more advanced than us. What would the mode of transportation, cities, “aircraft”, etc. look like? Now imagine that this Alien Civilization was 1,000 years more advanced than us. Would you recognize modes of transportation, the Entities themselves, etc. How about 5000 years more advanced than us… 20,000 more advanced than us… 100,000 years more advanced than us… 500,000 years more advanced than us… 1,000,000… The age of the Universe does allow for an Advanced Alien Civilization to exist - that is more than several Million years more advanced than us, if they (or some type of Natural Disaster) didn’t wipe themselves out. Would we even know if they were right next to us right now..? I do know one thing. They sure wouldn’t be crashing their poorly driven UFO’s in the desert.