The parallel planet theory is simply this. There is a galaxy that is exactly the same as ours. There is a planet exactly the same as Earth. This planet holds all the same qualities of this Earth, there is only one major difference. There is not a species of human on this planet which is reffered to as Earth2. The dominant species on Earth2 is the matin species. In the start, the power created four entities. The first two were an exact duplicate of himself, the second was a primordeal ape, the third was a feline. The power created these entites in the un-world. He sent one copy of himself and the ape to earth, and the other to entities to Earth2. When he sent them down the ladder to the separate planets the two entities combined and formed one entity. The ape and the copy formed a very unevolved human. The other copy and the feline formed an unevolved matin. The physical energy that comprises every living thig on Earth is also the exact same form of energy which exists on Earth2. That is why the energy can be recycled from planet to planet.