Search results
Results from the WOW.Com Content Network
The approximate age of the Moon, and hence the approximate phase, can be calculated for any date by calculating the number of days since a known new moon (such as 1 January 1900 or 11 August 1999) and reducing this modulo 29.53059 days (the mean length of a synodic month).
Due to tidal locking, the same hemisphere of the Moon always faces the Earth and thus the length of a lunar day (sunrise to sunrise on the Moon) equals the time that the Moon takes to complete one orbit around Earth, returning to the same lunar phase. While the Moon is orbiting Earth, Earth is progressing in its orbit around the Sun.
The Lunation Number or Lunation Cycle is a number given to each lunation beginning from a specific one in history. Several conventions are in use. The most commonly used was the Brown Lunation Number (BLN), which defines "lunation 1" as beginning at the first new moon of 1923, the year when Ernest William Brown's lunar theory was introduced in the American Ephemeris and Nautical Almanac.
A lunisolar calendar was found at Warren Field in Scotland and has been dated to c. 8000 BC, during the Mesolithic period. [2] [3] Some scholars argue for lunar calendars still earlier—Rappenglück in the marks on a c. 17,000 year-old cave painting at Lascaux and Marshack in the marks on a c. 27,000 year-old bone baton—but their findings remain controversial.
The Moon is Earth's only natural satellite. It orbits at an average distance of 384,400 km (238,900 mi), about 30 times the diameter of Earth. Tidal forces between Earth and the Moon have synchronized the Moon's orbital period (lunar month) with its rotation period at 29.5 Earth days, causing the same side of the Moon to always face Earth.
Because astronomical observation determines month length, dates on the calendar correspond to moon phases. The first day of each month is the new moon. On the seventh or eighth day of each month, the first-quarter moon is visible in the afternoon and early evening. On the 15th or 16th day of each month, the full moon is visible all night.
For premium support please call: 800-290-4726 more ways to reach us
A full moon sinking behind San Gorgonio Mountain, California, on a midsummer morning. Moonrise and moonset are times when the upper limb of the Moon appears above the horizon and disappears below it, respectively. The exact times depend on the lunar phase and declination, as well as the observer's location.