Question

why there is no atmosphere on the moon

Answer 1

Moon has no atmosphere because the value of acceleration due to gravity on surface of the moon is small

Answer 2

Moon has no atmosphere because the value of acceleration due to gravity 'g' on surface of moon is small. Therefore, the value of escape velocity on the surface of the moon is small (only 2-5 km s−1s−1). The molecules of the atmospheric gases on the surface of the moon have thermal velocities greater than the escape velocity. That is why all the molecules of gases have escaped and there is no atmosphere on moon.

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