There are those who say that hell is everywhere, that is, those in hell are free to roam the universe. The story of Lazarus and the rich man indicates that there is a definite separation between the good and the wicked, a great chasm that cannot be crossed separates them. Further, if the souls of the damned are bound to fire they cannot be everywhere in the cosmos.
Biblical references seem to indicate that hell is within the earth as follows "And they [demons] pleaded with him [Jesus] not to order them to depart to the abyss." (Lk 8:31) We also read how God punished the Israelites who complained against Moses, "the ground beneath them split open, and the earth opened its mouth and swallowed them and their families (and all of Korah's men) and all their possessions. ...They went down alive to the neither world...." (Nm 16:31-32) If it is true that hell is within the earth, where will the damned go when the earth comes to an end? Of course this would be no problem for God who can move them or they can move themselves to another fiery realm.
A more probable scenario would be for heaven to be an invisible dimension toward the center of the universe while hell would be at the outer fringes of the of creation. As there are many dwelling placed in heaven there also would be many hellish places suited to the degree of wickedness of the lost souls.
Both of these realms are invisible to us because God has imposed limitations on our sense perceptions even when aided by technology.
At the General Audience of Wednesday, 28 July 1999, the Holy Father stated:
"The images of hell that Sacred Scripture presents to us must be correctly interpreted. They show the complete frustration and emptiness of life without God. Rather than a place, hell indicates the state of those who freely and definitively separate themselves from God, the source of all life and joy. This is how the Catechism of the Catholic Church summarizes the truths of faith on this subject: "To die in mortal sin without repenting and accepting God's merciful love means remaining separated from him for ever by our own free choice. This state of definitive self-exclusion from communion with God and the blessed is called 'hell'" (Cathchsm of C.Ch, n. 1033).
The Pope is of the opinion that the biblical images of hell's fire is metaphoric language which impresses on us how awful hell is. This opinion goes back to the early church. Pope John says that hell is primarily a separation from God, which no one disputes, but the prefix "Rather than a place" leaves room for place. Indeed it must also be a place because spirits are subjected to matter which hinders them from moving where they will.
God's Justice and Hell