Image 1 Is parallel universe or multiverse theory science or science fiction? The answer is that theories are theories until they can be proven true or false. That's why we might say that multiverse is only a theory. But if a multiverse exists we can explain dark energy by using the multiverse theory as the base. And simply saying that outside gravitational effect from other universes causes the expansion of the universe. So the fact is that if the other universes exist they are there can we see them or not. The ability to observe the thing doesn't affect its existence. The thing that makes the dark matter so interesting is that is invisible to us. It's similar material with other materials. But we just cannot see it. There is no evidence about the existence of other universes. There was one big thing or hype that NASA has found the mirror universe. But that thing was a so-called false alarm. The article that caused that alarm was the highlight that "NASA has found
For finding solutions for problems, we must not claim that some proposition is right or wrong. All possibilities are open. Until they are proven right or wrong using empiric methods that are scientifically accepted.