The Moon
The Moon offers unparalleled celestial accessibility. Visible to the naked eye with a diameter half a degree across the night sky, it requires no telescope for appreciation. Approximately 7 billion humans can observe the Moon on any clear night, making it democracy's celestial favourite.
Only 12 humans have walked upon its surface, yet countless millions have photographed, painted, and pointed at it. The Moon is close enough for romantic association, far enough for aspirational dreaming. It hits, as they say, the celestial sweet spot.
Time
Time maintains perfect universal accessibility whilst remaining completely intangible. Every conscious being experiences time continuously, yet no one has ever touched, seen, or directly observed it. We perceive time's effects rather than time itself, much as we perceive wind through rustling leaves.
Time requires no clear skies, no equipment, no particular location. It is accessible in the deepest cave, the darkest night, the most confined space. One cannot escape time to gain perspective on it. This inescapable intimacy represents either ultimate accessibility or ultimate imprisonment.