different motion of moon.m
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Answer:
The Moon moves around the Earth in an approximately circular orbit, going once around us in approximately 27.3 days, or one sidereal period of revolution. As it does this its position changes, relative to the stars. ... The apparent motion of the Moon from hour to hour; each hour it moves about one diameter to the East.....
different motion of moon are :
1. Daily apparent revolution:
Like all celestial bodies, the moon appears to revolve around the Earth, once every 24 hours. This is caused by the rotation of the Earth. However, the moon revolves eastward in its orbit, ie: in the same direction as the Earth. Therefore, it takes a little longer for the earth to catch up, lengthening the apparent revolution to 24h 50m.
2. Daily growth and shrinking:
Since an observer is slightly closer to the Moon when it is at the zenith than when it is at the Horizon, the moon is slightly larger in apparent diameter at that time. This amounts to about 1 part in 120, or about 15 seconds of arc.
3. Synodic revolution:
The Moon appears to move from the right ascension of the Sun (New Moon) around the celestial sphere and back to the Right Ascension of the sun in 29d 12h 44m. The Moon's orbital speed is 632 wiles per second.
4. Rotation on its axis:
Although the Moon appears to have no rotation, it must, in fact, rotate once per revolution in order to keep the same face toward the Earth.
5. East-west Libration:
The moon appears to rock from side to side as it revolves around the Earth. This is because the Moon does not exactly face toward the centre of the Earth, but rather, toward the Centre of its orbit. Consequently, we see a bit around one side of the Moon, and then a bit around the other as a month passes.
6. Equation of the Centre:
If the Moon's orbit were circular the Moon would revolve at a constant speed. However, the orbit is elliptical so that the Moon travels faster at certain times, and slower at other times. This makes the Moon up to 6° early or late during the period of a month.
7. Evection:
Evection is the sun’s influence on the Moon. It causes the Moon to speed up and slow down in its orbit, causing the quarter phases to occur unevenly.