Uncreated - the Uncaused Cause
Science recognizes that in the natural world every effect must have a cause. There is always some explanation how each effect came about. There is always something that preceded each occurrence and that caused it.
Only God is not an effect. He is not created. He never came into being. There is nothing that existed before Him that explains His existence. He always is.
God possesses the ground of His existence in Himself. He exists by the necessity of His own being. it is His nature to be.
Only God exists by virtue of His very nature. The ground of our existence and of all creation is outside of ourselves — in Him. He is the ultimate Cause of all that there is.
(Spotlight 2, Lesson 2 in Doctrine 101: Learning about God)