nice done, but the bodies in universe dnt nesesery need to be half the size even if the mass is only the half (but mars shuld be 50% of the earths size. now it would be nice if someone could make a nebula model and so on. BTW, now whan you have done this mdels is it hard to change the lok of the planet? if not make different kind of planets, gas/ice/rock and different atmospheres like CO2(carbon diooxid) methane, hydrogen or any ki8nd of gas.