Where is the dust of the earth? Daniel the prophet wrote: 


  “And many of them that sleep in the dust of the earth shall awake,
  some to everlasting life, and some to shame and everlasting contempt”


(Dan. 12:2).

Where in the universe is the dust of the earth?
You're asking the wrong question. This isn't a place; it is a state.

"Sleep" is used hundreds of times throughout the Old and New Testaments as a euphemism or metaphor for death. Likewise, the theme of being created from the dust of the earth and then returning to it when we die is seen in several places. This is a reference to those that have died, not to any particular physical location.

This point isn't really a matter of opinion either. All major branches of Christianity, all Bible translators, commentators, and theologians agree on this general interpretation of the "dust" and "sleep" references in Scripture. The specific context in some cases might involve other interpretive difficulties, but the basic point that this and many similar references are to death is pretty much undisputed.