If what goes up must come down, what comes down that must go up?

Why this works

This riddle plays with the concepts of movement and perspective. The phrase "what goes up must come down" typically refers to gravity, like an object thrown into the air. However, in this case, "the sun" is the answer because it rises in the morning (going up) and sets in the evening (coming down). The clever twist is that while we see the sun ascend and descend in the sky, it also symbolizes the cyclical nature of day and night, where after it comes down, it will inevitably rise again.