The higher the dewpoint is, the more moisture that is in the air. The higher the dewpoint is above 65 F, the stickier it will feel outside (feels like you have to breathe in a bunch of moisture with each breath). 75 F or above dewpoint, the air really feels sticky and humid. RH can be more difficult to explain.
Unlike all of the other planets in the Solar System, Mercury is just bare rock. It does have a tenuous atmosphere, but ground and space-based observations see just the gray rocky color of Mercury. This gray color comes from Mercuryâs molten surface that cooled and hardened billions of years ago after the formation of the [â¦]
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).