The Prophet Joseph Smith taught, in the King Follett Discourse, that “God himself was once as we are now, and is an exalted man, and sits enthroned in yonder heavens!” [Teachings of the Prophet Joseph Smith, p. 345].
The corollary to this statement is the Prophet Joseph’s instruction that “You have got to learn to be Gods yourselves, and to be kings and priests to God, the same as all Gods have done before you, namely by going from one small degree to another…” [Teachings of the Prophet Joseph Smith, p. 346].
So this leads us to the obvious conclusion that since God was once as we are now, and since we can achieve the same position in the eternities as God has now – of necessity, although God is eternal and his kingdoms have no end, they did have a beginning. His Godhood began at some definable point in some sort of calculation of time, but will have no end. This is the same for us – although our intelligences are eternal and had no beginning – our attainment to Godhood will occur at a specific and definable juncture, while at the same time having no more end.
I’d like to throw in here my contention that although we may live in what we may consider our visible universe, there is not just one universe, but that there are likely an infinite number of universes beyond ours, beyond our grasp visibly, scientifically, and spiritually.
In any case, there was a time when our God, our Heavenly Father, began to be God. This may seem heretical but it must be true. And thus He began His dominion at some point in time, however that may be calculated.
W. W. Phelps, editor of The Times and Seasons in Nauvoo before and after the Prophet Joseph’s death, responded to correspondence he had received from William Smith, brother of the Prophet. This is what he said:
“And that eternity [the one during which Christ’s doings have been known], agreeable to the records found in the catacombs of Egypt, has been going on in this system [not this world] almost two thousand five hundred and fifty-five millions of years”
Bruce R. McConkie, in his series The Mortal Messiah, states that: “The papyrus from which the Prophet Joseph Smith translated the Book of Abraham…also contained this expression relative to what apparently is the universe in which we live, which universe has been created by the Father through the instrumentality of the Son.” [The Mortal Messiah, Book 1, p.32-33]. McConkie says that “Joseph Smith and the early brethren in this dispensation knew much that we do not know” and “this matter of how long eternity has been going on in our portion of created things is one of these matters”.
From these statements it appears that Joseph Smith revealed that our universe, or system, was 2.555 billion years old.