That's because we think Mars used to have a wetter past, and when water had enough energy, it broke up into hydrogen and oxygen, and hydrogen being so light, it escaped into space, and the oxygen that was left oxidized or rusted the ground, making that familiar rusty red color that we see.
Ne mendojme se Marsi ka patur nje te kaluar me lageshtire, dhe kur uji kishte energji te mjaftueshme, u nda ne hidrogjen dhe oksigjen, mirepo duke qene i lehte hidrogjeni u leshua per ne hapesire, dhe oksigjeni qe ngeli u oksidua ose ndryshku dheun, qe u kthye ne kete ngjyren e kuqe te ndryshkut qe shohim ne.