Let's break this one down, 
I got inspired by the wheels within a wheel while
reading Ezekiel Chapter 1--It made me think of an atom, 
and the atom as we know is one of the basic bulding blocks for matter
at least from what we have discovered so far. 
I added a fire inside the atom to symbolize the fiery spirit of man, 
blue, for contrast. 
The tree and planet are symbolic of heaven
and earth, while also representing how granduer all of creation is.