The same refers to the micro-world. I dare say that the smallest physical entity is a constituent of magnetic field. More:http://www.eioba.com/a/38yy/what-is-magnetic-field
There is of course, equilibrium. Omnipresent universal magnetic field beyond universal nucleus (materialized part of the universe) counterpoising universal nucleus (all physical entities along with magnetic field within it).”
Note that your first two sentences objectify motion. Radiation does not exist, it occurs. Radiation is motion. Space cannot “contain” radiation (see EMIPE). I agree with you, however, that space contains a medium for the propagation of radiation. This medium is physically and logically necessary. Once we have such a medium, we do not need to objectify the motion that it transmits.
This shows the logical struggle you are having by maintaining your belief in finity, as clearly shown by your comment that: “There are no infinities in nature. So, the universe must be finite.” You must realize that, as shown in Borchardt (2004) and Chapter 3 of Borchardt (2007b), this is purely an indeterministic assumption, although it is surely popular with the mainstream. Nature actually is filled with infinities at every turn. That is why there are never two identical snowflakes, no really identical twins, and a plus or minus for every measurement. Each person and each microcosm is unique because each consists of an infinity of smaller and smaller submicrocosms and exists within a macrocosm that contains smaller and smaller supermicrocosms. The signs of infinity are everywhere.