Question

Determine the escape velocity of a body from the moon. Take the moon to be a uniform sphere of radius 1.74 x 10⁶m and mass 7.36 x 10²² kg. Does your answer throw light on why the moon has no atmosphere? (G = 6.67 x 10^-11Nm² /kg²

Answer 1

Escape velocity from the surface of the moon is, 

where, 

M is the mass of the moon, and 

R is radius of the moon. 

Here, we have

Since escape velocity for the moon is 2.38 km/sec which is small as compared to the average speed of gas molecules at the moon, therefore the moon cannot bind the atmosphere.