The color of the night sky isn't simply black; it's surprisingly complex and variable. While often depicted as dark blue in cartoons for simplicity, the actual color depends on several factors.
Factors Affecting Night Sky Color
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Moonlight: When the moon is out, its light scatters in the atmosphere similarly to sunlight, resulting in a blue hue, much like the daytime sky. This is because the same atmospheric molecules that scatter blue light during the day also scatter moonlight at night. [Source: Multiple sources indicate moonlight's effect on night sky color, including the reference mentioning that moonlight scatters in the same manner as sunlight making the nighttime sky blue.]
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Airglow: Away from city lights, a phenomenon called airglow contributes to the night sky's color. This faint emission of light from the upper atmosphere produces a mix of blues, greens, and reds. [Source: Science Buffs article explicitly states that airglow causes a mix of blues, greens, and reds in the night sky.]
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Auroras: The spectacular auroras borealis (Northern Lights) and aurora australis (Southern Lights) introduce vibrant colors like green, red, purple, and even blue, depending on the altitude and type of atmospheric particles interacting with solar particles. [Source: Atlas Obscura article mentions the possibility of reddish green, teal, or purple in the night sky, hinting at the aurora's influence.]
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Light Pollution: City lights significantly alter the perception of the night sky's color, washing out the fainter colors produced by airglow and moonlight. Under heavy light pollution, the sky might appear a very dark gray or black. [Source: Several references implicitly or explicitly mention the impact of light pollution on night sky color perception.]
In Summary
The night sky's color is not a single shade but a spectrum influenced by moonlight, airglow, auroras, and the level of light pollution. While a dark blue is a common depiction, in reality, it can range from a deep navy blue under moonlight to a mix of colors, including greens, reds, and purples, especially in areas with minimal light pollution.
