Alma 40:3

"...Now, I unfold unto you a mystery; nevertheless, there are many mysteries which are kept, that no one knoweth them save God himself. But I show unto you one thing which I have inquired diligently of God that I might know- that is concerning the resurrection."

Alma here shows that is is possible to receive additional knowledge/light directly from God. This comes through diligent study, pondering, reading the scriptures, and prayer.  God is not closed off to the world at all.  He loves to share what He knows to those who are humble and truly seek knowledge from Him.  Our Heavenly Father is so loving that he will answer our prayers and inquiries as we ask with faith, patience, and sincerity.