One of the possible universes that comes out of string or rather M theory is the accordian universe. In this universe, during the big bang, the universe folds up into several overlapping concurrent universes, that presumably are connected at the edges of the universe.
Light and other fields are trapped in each fold, except for gravity. Since gravity is something like space itself, according to General Relativity, it permeates all the overllaping folds. So it is expected that stars and planets live on each fold, but they cannot see each other since light is trapped in each fold or layer (or membrane in M theory). The light in all folds will eventually get here, but since we cannot even see to the edge of the universe, the light from all the other layers has not arrived yet. In fact, because of the expansion of the universe, it may never get here. Only the gravity from all the invisible stars and planets in the other layers is felt by us.
So this is yet another explanation for what is in dark matter. If correct, and if every layer is basicaly the same, at least as far as the amount of mass in it is concerned, then we can calculate the number of layers local to us. In round numbers, 5% of the omega of the universe is visible matter and 35% is dark matter. The remaining 60% to make the universe flat is dark energy. (Dark energy is what is making the universe expand at an accelerating rate).
So we know that the number of layers in dark matter is roughly 7. That plus our layer makes 8 layers all together. Black holes connect all the layers as a black hole in our layer must also be one in all the other layers, even if you do not think about it.
The view of some physicists is that particles with high mass like protons exist in our layer, but particles with low mass like electrons and neutrinos and axions exist in the other layers as high mass particles. Just because they are in another layer, we experince their mass as low. That may also be why electrons are rather diffuse compared to nuclei. The collapse of wave functions for an electron is then explained as the other layer particle coming into our layer momentarily at a point to exchange energy. So in this model, contrary to my views expressed previously, electrons are particles, like point particles, in the next layer. We just cannot locate them precisely from this layer.
But what I find most interesting is that many religions, especially those in the west, claim that there are seven heavens. In mystical Judiasm, god exists in the seventh heaven, and through meditation, the jewish mystics of about 1000 years ago claim to have been able to pass through the gates from heaven to heaven using mantras containing the names of god. The story is that these names would fool the angels that guard the gates. But they would only be fooled once, maybe per person, and so the mantras got to be more and more elaborate as the same mystics tried to take the journey over and over. Soon the mantras filled entire books that still exist. And soon the angels could not be fooled. So the practice would cease until the next generation came along.
The point for me is that I keep finding elements of physics that support scripture, with some amount of interpretation I admit. Perhaps there are wormholes for passing from one layer to another that are not destructive to life or consciousness, especially if you are already dead...