The sky is actually not light at night. It appears dark, with only the light of the stars, moon, and sometimes artificial sources like city lights visible.

Here's why:

* Sunlight: The light we see during the day is sunlight scattered by the Earth's atmosphere. At night, the sun is on the other side of the Earth, so its light doesn't reach us directly.

* Darkness: Without sunlight, the sky becomes very dark.

* Stars: The faint light we see from stars is actually quite distant and weak.

* Moon: The moon reflects sunlight, giving us some light at night, especially during a full moon.

* Artificial Light: Cities and other human settlements produce a lot of artificial light, which can illuminate the sky in urban areas.

So, while the sky might appear slightly brighter in some areas due to artificial light, it's essentially dark at night because there's no direct sunlight.