Scene Context: After sunset, the sky transitions from a rusty red to a cold, sapphire-blue haze.
Essence of the Phenomenon: A Martian sunset does not look like an Earth sunset. Because of the extremely fine dust in the atmosphere, light scatters differently: near the sun, blue wavelengths can penetrate more effectively than red ones.
Scientific Basis: Observations by the Curiosity rover have explicitly shown that on Mars, the twilight sky near the sun can take on a bluish tint specifically due to the properties of the fine atmospheric dust. The sapphire-blue hue of Martian twilight is driven by a real atmospheric light-scattering effect.