Our earth can hold our atmosphere whereas Mars cannot. So the atmosphere retention mass must be between the masses of Mars and Earth, but if mass is to be considered then can an iron ball having the same mass of the earth hold an atmosphere of its own?
Also since larger planets can hold larger atmospheres, if a planet like Jupiter was like the Earth in composition and the atmosphere contained gases in the same ratio as here on earth, will it result in the atmosphere being modified to suit the conditions of higher pressure and gravity of the planet?
What kind of atmospheric changes could be expected?
Can a very large planet result in the liquefaction of gases (I know that planet size is not the prerequisite for the presence of liquified gases but), if it does, can it be due to gravity alone?