The moon sky is dark compared to blue sky of the earth because

Concept:

1. Earth's Atmosphere: The Earth has a thick atmosphere composed mainly of nitrogen, oxygen, and other gases. - Light from the Sun is scattered in all directions by the gases and particles in Earth's atmosphere. - Blue light is scattered more than other colors because it travels in shorter, smaller waves. This is why the sky appears blue during the daytime.
2. Moon's Lack of Atmosphere:- The Moon, on the other hand, has a very thin and negligible atmosphere, which is often referred to as an exosphere. - Without a significant atmosphere, there are no particles to scatter sunlight. - As a result, the sky on the Moon remains dark even when the Sun is shining.
3. Escape Velocity and Atmospheric Retention:- The Moon’s lower escape velocity means that it cannot retain a thick atmosphere because gas molecules have sufficient energy to escape the Moon’s gravitational pull. - This lack of atmosphere results in no scattering of light, leading to a dark sky.

Explanation:

• The key reason for the dark sky on the Moon, in contrast to Earth's blue sky, lies in the presence (or absence) of an atmosphere and the scattering of light.
• On Earth, the atmosphere scatters sunlight, particularly blue light, which makes the sky appear blue.
• The Moon, lacking such an atmosphere, does not scatter sunlight, and thus the sky remains dark.
• While the Moon's escape velocity and smaller size are related factors, the direct reason for the dark sky is its lack of a substantial atmosphere to scatter sunlight.

Conclusion:

The correct answer is Moon has less escape velocity