Chapter 3: Light Pollution From the World Below

Many flights travel over densely populated regions where artificial lighting extends for hundreds of miles.

Large cities produce enormous amounts of light that travel upward into the atmosphere. This creates a glowing dome often visible from great distances. Scientists refer to this effect as skyglow, one of the most common forms of light pollution.

When an aircraft flies above urban areas, passengers may see bright networks of roads, neighborhoods, and industrial centers. While impressive, these lights can significantly reduce contrast between the night sky and celestial objects.

Clouds can make the situation even worse. Rather than blocking city lights, low clouds often reflect and scatter them, increasing brightness below the aircraft. The resulting glow can overpower dim stars that would otherwise be visible.

Travelers flying over oceans or remote wilderness areas frequently report better star visibility because there are fewer artificial light sources affecting the sky.