Why is a day on Mars called a sol?
Photo Credit: Courtesy of 3DStockPhoto (Mars image)
Sol (borrowed from the Latin word for sun) is a Mars solar day; that is, a Mars-day. ... It is one of several units for timekeeping on Mars. The sol was originally adopted in 1976 during the Viking Lander missions and is a measure of time mainly used by NASA when, for example, scheduling the use of the Mars rover.