Why is this the answer?

The answer is moon because this is a super clever riddle about the big, bright object we see in the night sky. Let's look closely at all the amazing hints it gives us. The first part says, "I am the hole in the night." Think about what the sky looks like when the moon is out. The night is a deep black, but the moon shines so brightly that it looks like a big, glowing circle punched out of the darkness. It is a shining, silvery opening in the black sky, just like a wonderful "hole" made of light. Then, the riddle calls the answer "the ever watchful eye." Imagine the moon is a huge, round eye looking down at Earth. It is always up there, seeming to watch over us all night long while we sleep. People have felt for thousands of years that the moon is always observing everything that happens down below. It is always present, whether you can see it clearly or not. Even when it is just a tiny curve of light, which is called a crescent moon, you know it is still up in the dark sky, keeping a quiet eye on all the cities, oceans, and forests. The most important clue comes last: "I return in a cycle, to enlighten the sky." This is a wonderful way to talk about the moon's different shapes. The moon doesn't always look the same. We know it has phases, like when it is a full circle or when it is a tiny, thin line. These shapes repeat in a regular pattern that we call a cycle. This means it comes back and looks the same at regular times. Once the full moon comes back around, it "enlightens" or brings light to the night sky, helping people see even after the sun has gone down. The moon's light makes the night less scary and much more beautiful. The moon perfectly fits every single part of this fantastic riddle.