Explanation:

God enters the bodies, which are relevant to the concerned worlds. In Preta Loka, God is having gaseous body which is partially energized. God here is called as Dharma Deva, who enquires the souls and gives judgment regarding their lines of journey. Some of these souls have very strong attachment to the world even after death and hence they are thrown down to martya loka by God pending the enquiry. They roam in this world as ghosts for sometime and then face the enquiry. The same God exists in the relevant bodies in hell (Naraka Loka) and Pitru Loka called as Yama. The body of Yama in hell is black, whereas it is of golden color in Pitru Loka, which represents the light of the moon. This black color is due to the major component of gaseous smoke in the body. Hence, the composition of matter and energy changes from sub-world to sub-world in the case of the same deity, Yama. This is an indication of the increase of intensity of radiation and a decrease of matter in the body as we go up.