Relative humidity. Relative humidity (RH) is the ratio of the partial pressure of water vapor to the equilibrium vapor pressure of water at a given temperature. Relative humidity depends on temperature and the pressure of the system of interest. It requires less water vapor to attain high relative humidity at low temperatures; more water vapour is required to attain high relative humidity in warm or hot air.
silver is the color of the element mercury silver is the color of the element mercury Silvery.
The contrast between the colors of the Caloris basin floor and those of the surrounding plains indicate that the composition of Mercury's surface is variable. Many additional geological features with intriguing color signatures can be identified in this image. For example, the bright orange spots just inside the rim of Caloris basin are thought to mark the location of volcanic features, such as the volcano shown in this previously released Narrow Angle Camera (NAC) image (see PIA10942).