When they got on Mars they realized that it looked like a human face and they wanted to know if it was left by an alien or something. In order for the face to be created by aliens we would have to know that they exist. We would have to actually know that aliens made the face on Mars, we would have to have evidence that they exist. In order to know that the face is a natural landform we would have to do a lot of research stating that maybe something or someone made the face. Scientist would have to make sure that it is a face and not something else. Scientist figured that is was just another Martian mesa, common enough around Cydonia, the unusual shadows made it look like an Egyptiazn Pharaoh. They would have to do research to see if aliens left it there or if its something that someone or something left on Mars. In order to find out if it's a face they would have to make conclusions about what it may be. They figured that it did not have anything to do with aliens but they were not sure if it was true or not they wanted to know if alien marking were hidden by haze.