Images sent back by European probe Mars Express show a crater on the Red Planet that looks a little bit like a “happy face”, say scientists. The image shows a ‘smiling’ row of rocky mountains sitting within a crater known as the Galle Crater. Two ditches can also be seen on the image of Galle which could be a sign of liquid water running on Mars’ surface. A Nasa orbiter has also sent back its first colour image after arriving at Mars on March 11.