The Earth and the Moon differ greatly in their ability to hold an atmosphere.
PHYSICS · Multi-part · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
The Earth and the Moon differ greatly in their ability to hold an atmosphere.
(i) Define escape velocity.
(ii) Using suitable reasoning, explain why the Moon is unable to retain a substantial atmosphere while the Earth can.
(iii) If a planet’s mass is kept constant but its radius is doubled, qualitatively describe how this change would affect its ability to retain light gases. Give reasons for your answer.