Mars was once a habitable planet and its where humans originally came from. Due to a great war, Mars was heavily damaged and humans needed to look for another planet. They chose Earth, however, it was roaming around with dangerous dinosaurs that wouldnt hesitate to chew up anything in its sight. So the humans built a spaceship and locked themselves onto Earths orbit. The spaceship then opened up and fired a projectile into Earth, that would then cause the extinction of the dinosaurs. Still to this day you can see the spaceship around Earths orbit, we call it the moon.