Search results
Results from the WOW.Com Content Network
A lunar phase or Moon phase is the apparent shape of the Moon 's directly sunlit portion as viewed from the Earth (because the Moon is tidally locked with the Earth, the same hemisphere is always facing the Earth). In common usage, the four major phases are the new moon, the first quarter, the full moon and the last quarter; the four minor ...
Lunar day. A full lunar day observed from the Earth, where orbital libration causes the apparent wobble. A lunar day is the time it takes for Earth 's Moon to complete on its axis one synodic rotation, meaning with respect to the Sun. Informally, a lunar day and a lunar night is each approx. 14 Earth days. The formal lunar day is therefore the ...
In lunar calendars, a lunar month is the time between two successive syzygies of the same type: new moons or full moons. The precise definition varies, especially for the beginning of the month. Animation of the Moon as it cycles through its phases, as seen from the Northern Hemisphere. The apparent wobbling of the Moon is known as libration.
The original Roman calendar is usually believed to have been an observational lunar calendar [2] whose months ended and began from the new moon. [3] [4] Because a lunar cycle is about 29.5 days long, such months would have varied between 29 and 30 days. [5]
The full moon is the lunar phase when the Moon appears fully illuminated from Earth's perspective. This occurs when Earth is located between the Sun and the Moon (when the ecliptic longitudes of the Sun and Moon differ by 180°). [3] This means that the lunar hemisphere facing Earth—the near side —is completely sunlit and appears as an ...
A lunar calendar is a calendar based on the monthly cycles of the Moon 's phases (synodic months, lunations), in contrast to solar calendars, whose annual cycles are based on the solar year. The most widely observed purely lunar calendar is the Islamic calendar. [a] A purely lunar calendar is distinguished from a lunisolar calendar, whose lunar ...
Lunar node. The lunar nodes are the two points where the Moon's orbital path crosses the ecliptic, the Sun's apparent yearly path on the celestial sphere. A lunar node is either of the two orbital nodes of the Moon, that is, the two points at which the orbit of the Moon intersects the ecliptic. The ascending (or north) node is where the Moon ...
Saros (astronomy) The saros (/ ˈsɛərɒs / ⓘ) is a period of exactly 223 synodic months, approximately 6585.321 days (18.04 years), or 18 years plus 10, 11, or 12 days (depending on the number of leap years), and 8 hours, that can be used to predict eclipses of the Sun and Moon. One saros period after an eclipse, the Sun, Earth, and Moon ...