Space/time is the visible, physical realm that we now experience as conscious, incarnate beings. This is the realm of physics and the proverbial five senses. Time/space is the invisible, metaphysical realms, also known as the inner planes. This is the realm of intention and the unconscious. The terminology is likely based upon the theories of physics of Dewey Larson, used by Don and Ra to integrate this scientific understanding with the spiritual understanding.
Space/time and time/space are complex and complete systems that form fundamental aspects of our illusion. They share an inverse relationship due to the inequality between time and space. In space/time, the spatial orientation of material causes a tangible framework for illusion. In time/space, the inequality is shifted to the property of time.
These space/time and time/space distinctions, as we understand them, do not hold sway except in third density. However, fourth, fifth, and to some extent, sixth densities, work within some system of polarized space/time and time/space.
Note: Ra also uses the term “time/space” to indicate the passage of clock and calendar time as we know it.