According to Vedic Cosmology, there are countless universes, which are clustered together like foam on the surface of the Causal Ocean. The universes are separated from each other by the shell that envelopes each universe. Although the universes are clustered together, interactions between the universes are impossible. Each universe is completely protected by an enormous shell. Thus, each universe has a boundary. The universe is ball shaped and surrounded by an eight-fold shell. This shell is composed of primeval material elements in their most subtle manifestation. The shell consists of eight spherical layers in which each successive material element is manifested and stored. If we penetrate the universal shell consisting of these eight spherical layers, we will enter the universal globe and find a hollow region containing all the inhabited planets.
According to Vedic physics, space inside our universe is multidimensional. There are 64 main dimensions and each dimension is further divided into many sub-dimensions. Since the inhabitants of earth can only perceive three dimensions, their senses have no access to many other realms of universal reality. Therefore, we are unable to perceive many other planets and their inhabitants. Furthermore, there are other planets which we can perceive but at the same time we cannot see their inhabitants.
According to Vedic physics, different planetary levels have different time scales. Relativity of time is elaborately described in the Vedic literatures.
"Comparative Cosmology" by Akif Manaf J., Ph.D.
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Interesting to say the least....must research it some more...