Why is there no atmosphere on the Moon?
Solution 2E Introduction Atmosphere is a layer of gases that surrounds a planet. It is composed of different types of gas molecules. Since it is composed of gases, there will be a pressure exerted by the gas molecules in the atmospheric system which is referred as “atmospheric pressure”. Step 1 Here, our question is, why there is no atmosphere on moon. First we should understand what is the force which keeps the atmosphere always in ‘place’. It is nothing but the gravitational force exerted by the planet which holds the molecules in the atmosphere. Moon’s gravitational force is almost 1/6 times less than that of earth. That is, a man with 60kg weight will experience only 10 kg on moon (acceleration due to gravity on moon = 1.662 m/s ). 2 So, the gravitational force of moon is considered to be very weak while comparing it with that of earth. That is, moon will not be able to hold the gas molecules in its atmosphere due to this weak gravitational force. If any gas formation is occurred on moon, it will fly off into the space. Conclusion The weaker gravitational force prevents the formation of atmosphere on moon.