Regarding physics, and whether there are differences throughout the Universe. Where there are differences in how matter acts between the densities, there is no difference within a density. Life on other worlds is, of course, adapted to the chemical and mineral mix indigenous on the planet. Some are silicon based, where Homo Sapiens, for instance, is carbon based. The primary difference is in adaptation to radiation, the intensity of a given sun or other heat source. Your sun is of moderate intensity, but there are some worlds which you could not visit in your physical form. You would fry or quickly sicken. There are other worlds which you could not visit in physical form because of the chemical and mineral mix. You would become poisoned. These are some of the reasons why all intelligent life forms have not been presented to our contactees, during any adaptation orientation such as the one our emissary, Nancy, underwent. Consequently, the Zetas have not seen all that much of the Universe either. Since the issues and the spiritual work to be done are the same, it does not matter.