It is a journey through the known scales of the Universe, from the farthest cosmic expanse (macrocosm) down to the subatomic quantum level (microcosm). The human being lies somewhere in the middle of this seemingly infinite continuum, the conscious nexus of experience.
Here's a video version in HD:
There have been other attempts to visually represent the vast scales of inner & outer space, some of which I have posted before:
• Scale of the Universe 2
• Powers of Ten (10)
• The Known Universe
All these are tools for our minds to help comprehend the incomprehensible- the very nature of the Universe of which we are an integral part.