Answer – If the sidereal period is being considered, the Moon takes 27.3 days to orbit the Earth. Alternatively, if the synodic period is being considered, then it takes 29.5 days.
Explanation:
The Moon revolves around the Earth in its elliptical orbit in space. This movement takes 27.3 days and is known as the sidereal period. During this time, the Earth also simultaneously orbits the Sun.
On the 27th day of the sidereal period, the Earth’s revolution causes sunlight to strike the Moon at a marginally different angle than on the zeroth day. The Moon takes an additional 2.2 days to travel further and reach a position where sunlight hits it the same way as on day zero. This leads to a total of 29.5 days for the Moon to transition from one new moon to the next. The longer duration indicating the completion of all the phases of the Moon is called the synodic period.
Thus, depending on the basis of consideration, the duration of the Moon’s revolution around the Earth may either be 27.3 days or 29.5 days.
