Lunar swirls

Lunar swirls are enigmatic features found across the Moon's surface, which are characterized by having a high albedo, appearing optically immature (i.e. having the optical characteristics of a relatively young regolith), and (often) having a sinuous shape. Their curvilinear shape is often accentuated by low albedo regions that wind between the bright swirls. They appear to overlay the lunar surface, superposed on craters and ejecta deposits, but impart no observable topography. Swirls have been identified on the lunar maria and on highlands - they are not associated with a specific lithologic composition. Swirls on the maria are characterized by strong albedo contrasts and complex, sinuous morphology, whereas those on highland terrain appear less prominent and exhibit simpler shapes, such as single loops or diffuse bright spots.