section_path: Position and appearance/Albedo and color
section_name: Albedo and color
paragraph_text: Albedo and color
  
  The Moon has an exceptionally low albedo, giving it a reflectance that is slightly brighter than that of worn asphalt. Despite this, it is the brightest object in the sky after the Sun. This is due partly to the brightness enhancement of the opposition surge; the Moon at quarter phase is only one-tenth as bright, rather than half as bright, as at full moon. Additionally, color constancy in the visual system recalibrates the relations between the colors of an object and its surroundings, and because the surrounding sky is comparatively dark, the sunlit Moon is perceived as a bright object. The edges of the full moon seem as bright as the center, without limb darkening, because of the reflective properties of lunar soil, which retroreflects light more towards the Sun than in other directions. The Moon's color depends on the light the Moon reflects, which in turn depends on the Moon's surface and its features, having for example large darker regions. In general, the lunar surface reflects a brown-tinged gray light.
  
  At times, the Moon can appear red or blue.It may appear red during a lunar eclipse, because of the red spectrum of the Sun's light being refracted onto the Moon by Earth's atmosphere. Because of this red color, lunar eclipses are also sometimes called blood moons. The Moon can also seem red when it appears at low angles and through a thick atmosphere.
  
  The Moon may appear blue depending on the presence of certain particles in the air, such as volcanic particles, in which case it can be called a blue moon.
  
  Because the words "red moon" and "blue moon" can also be used to refer to specific full moons of the year, they do not always refer to the presence of red or blue moonlight.