Question

Give reasons:

The sky appears dark to passengers flying at very high altitude.

Answer 1

The sky appears dark to passengers flying at very high altitudes because there are fewer air molecules to scatter sunlight. At lower altitudes, the Earth's atmosphere contains a high density of air molecules that scatter sunlight in all directions, causing the sky to appear blue (Rayleigh scattering). However, at higher altitudes, the air is much thinner, reducing scattering. As a result, there is less diffusion of light, and the sky appears dark or black to passengers in high-altitude flights.