Akasa is present in the lightest gases and the most dense solid. It is sometimes termed, Matter Itself. In its highest manifestations it cannot be perceived except by the most evolved minds. Akasa is at a core of the World Cycles. Perhaps most importantly for us is to know that there is no big, no small and that the Absolute is within each of us.
Advance Course in Yogi Philosophy and Oriental Occultism by Yogi Ramacharaka