This photo obtained from Nasa yesterday shows a colourful view of Mercury produced by using images obtained during MESSENGER’s primary mission. These colours are not what Mercury would look like to the human eye; the colours are added to emphasise the chemical, mineralogical, and physical differences between the rocks that make up Mercury’s surface. Young crater rays, extending
radially from fresh impact craters, appear light blue or white. Medium- and dark-blue areas are a geologic unit of Mercury’s crust known as the ‘low-reflectance material’, thought to be rich in a dark, opaque mineral. Tan areas are plains formed by eruption of highly fluid lavas. The giant Caloris basin is the large circular tan feature located just to the upper right of centre of the image. MESSENGER stands for MErcury Surface, Space ENvironment, GEochemistry, and Ranging, a robotic spacecraft orbiting the planet.
