For my part I know nothing with any certainty, but the sight of the stars makes me dream
Dreams are a way for your subconscious to release any pent up worries or frustrations, and for you to visualize your goals and objectives in life. Everyone dreams, even if these subconscious movies are not remembered when you wake up. Dreams are different from nightmares because dreams are typically pleasant while nightmares are terrifying or disturbing in some way.