As particular, complex tuned resonant cavities (like the tone created when you blow across the top of a small, glass soft drink bottle) are "rang" by space and time impacting them, over the creation-to-death span of their existence there is a signature INSIDE THIS BLOCK OF SPACE-TIME which exists forever as all space for the entire Universe continues to implode down and inward from infinite expanse (which never began) toward the one infinitesimal Singularity (that never can end and is engaged in infinite velocity AND angular diversity).

This block of resonating space-time presence is a portal that can serve kind of like a "stargate (very poor rendition of what it really is)" to other such tuned portals IF on the same set of "frequencies". There is no space or time between tuned portals.