Parallel Universes

There are countless material universes in existence, all existing side by side, connected by the occasional portal, but for the most part unable to affect each other. The best explanation for these parallel worlds is that the many-worlds interpretation of quantum physics is correct and that at every instance hundreds of parallel worlds split off from our own, though this explanation has problems.

There are 6 known types of parallel universe.

1) Exotic universes. These appear to be universes that violate the laws of physics.

2) Starless voids. These appear to be empty universes, though it may simply be that the portal to them has opened in deep space. Regardless, there are no visible stars and no matter on the other side of the portal.

3) Starry voids. The portal leads to a vacuum, but there are visible stars. This implies that the universe is not empty, but there is no planet where Earth is.

4) Death dimensions. The portal leads to within a star, planet or similar and those who pass through it are destroyed by heat, gravity or asphyxiation

5) Parallel Earths. The portal leads to the surface of a planet much like Earth, though there may be a different atmosphere and/or different life forms. This is the type of parallel universe most easily reached- there are many rituals to open portals to different Parallel Earths- as well as those most profitable to visit when searching for xenotech.

6) Alternate Histories. The portal leads to an Earth where humans evolved and the continents and atmosphere are the same as on our Earth, but there has been a divergence at some point. There are less than a dozen such universes known, of which only 3 can be reached reliably by portals. The closest universe to our own is Naziworld, the others diverged far less recently.