text: As the moon is round, I think even if it is upside down, we won't notice it. Because a circle remains a circle whether looked from up, down, right or left.\nAlso the moon is completely white. If it was different colours we would have known whether it was upside down .ie. by looking at the colour's position.\n\nIt is a very puzzling question! I answered what I think. I am not sure whether my theory is right or wrong.\nGood question! You made me rack my brains really hard :)