Burt That is realistic thinking that firsr came the rock and metal core
that had enough gravity to have the force to hold gasses around it. Mars
much smaller than the Earth only has 1% as much atmosphere. Thus Mars
atmosphere can only be two heavy gases 95% CO 2.7 % Nitrogen Jupiter on
the other hand started with a rock core so great(15 times greater than
Earth) can hold the lightest gas hydrogen,and that maKES IT A GAS
PLANET.