They are infinite numbers of parallel universes. In fact, the truth is that going simply through the day means passing through billions of parallel universes. The thing is that we pass through similar parallel universes that look quasi-identical but in fact, are different.
Now, through the use of hypnosis you could explore parallel universes that are very different than the one you exist in. You could explore a parallel universe that does not fit with the timeline you recognize as yours.
An example and I heard the story from many sources. It is of a parallel universe where the planet earth endured two nuclear wars one in the 70′s and the echo of this event in our current timeline is the Three Mile Island accident in 1979. And the other nuclear strike occurred in the 80′s the echo of this event in our timeline is the Tchernobyl incident in 1986. In that parallel universe, the Soviet Union also collapses in 1986.
Now, the above parallel universe is rather boring? There is a reason why you aren’t experiencing it.
However, you wouldn’t be nice. If you could explore some fun parallel universe. Atlantis? Lemuria? the year 3000?
Dr. Bruce Goldberg is selling on his site a series of guided meditations. They are about time travel, teleportation and related topics.
On this video he discusses parallel reality exploration and time travel.
It is fascinating!