What are we truly seeking when we gaze at the moon in the starry sky? Is it a longing for the unknown, or a reflection on our own existence?

Friend, that's an excellent and deeply insightful question you've asked. I actually don't see these two aspects as contradictory; they're more like two sides of the same coin, or perhaps even more facets. That complex feeling we experience when we look up at the moon is really a tapestry woven from many threads.

Let me try to share my thoughts by breaking it down into a few aspects.

Firstly, the moon acts like a "mirror" hanging in the sky, reflecting ourselves

This might be what you meant by "reflection on our own existence."

Emotional Projection: Have you noticed that when you're happy, the moon seems bright and pure, but when you're sad, it feels cold and lonely? Li Bai wrote, "I lift my head to gaze at the bright moon, then lower it, thinking of my homeland." Su Shi penned, "Men have sorrow and joy, they part or meet again; The moon is bright or dim and she may wax or wane." The moon itself doesn't change; it's our state of mind that shifts. We project our longing, loneliness, joy, or sorrow onto the moon. It becomes a vessel for our emotions, a silent confidant.
Temporal Reference Point: The moon has hung there for thousands, millions of years. It has witnessed Earth's transformations, the extinction of the dinosaurs, and the rise and fall of human civilizations. When we gaze up at it, we instinctively feel a sense of time and space. In comparison, don't our personal troubles and the brevity of our lives seem insignificant? This feeling pulls us out of our daily trivialities and prompts us to ponder bigger questions: Who am I? Where do I come from? What is the meaning of my existence? This is an existential reflection.
Shared Solace: The most wondrous thing is that no matter where you are on Earth, whether wealthy or penniless, we all see the same moon. As the ancients said, "Though we are far apart, we share the same moon tonight." When you feel lonely, the thought that distant loved ones, friends, or even people from millennia ago have gazed upon this same moon creates a sense of connection across time and space. We are no longer isolated individuals but part of the larger human story.

Secondly, the moon is also a "destination," representing our yearning for the unknown

This aligns with the "longing for the unknown" you mentioned.

Pure Curiosity: Long before science advanced, people were filled with fantasies about the moon. Are Chang'e and the Jade Rabbit there? Why does it shine? Why does it wax and wane? This primal curiosity is the fundamental driver of human exploration and progress. We want to know what it's like "out there," to lift its veil of mystery.
Symbol of Courage: From Galileo first pointing his telescope at the moon and seeing its cratered surface, to Armstrong taking "one small step for man, one giant leap for mankind" on its surface, the moon has always been one of the ultimate goals of our exploratory spirit. It represents human curiosity, courage, and the instinct to "reach outward." Looking up at the moon, we see not just a celestial body, but a monument to human dreams and achievements.
Future Possibilities: Now, we talk about returning to the moon, establishing lunar bases, even using it as a stepping stone to Mars. The moon is no longer just poetry and distant dreams; it has become a concrete, plannable future. When we gaze at it, we are also imagining the next steps for human civilization. This vision of the future is itself a profound longing for the unknown.

To summarize

So, what are we really seeking when we look up at the moon in the night sky?

I believe we are looking both inward and outward.

Looking inward, we see it as a mirror, reflecting on our own lives, emotions, and place in the universe under its eternal gaze.

Looking outward, we see it as a destination, drawn by its mystery, igniting our desire to explore the unknown and push boundaries.

These two feelings often occur simultaneously. We yearn to explore the vastness of the cosmos because we feel our own smallness; and conversely, exploring the distant unknown makes us return to cherish our own existence even more.

Simply put, when we gaze at the moon, we are seeking both the spiritual home that holds our nostalgia and loneliness, and the cosmic frontier that inspires us to keep moving forward.