How long does it takes the moon to rotate the earth?

Answer 1

The moon orbits the earth in a little under 28 earth days. It travels at almost 2,290 miles per hour. Coincidentally, the moon's rotation period is also a little under 28 days, meaning the same face points toward the earth during its entire orbit. The English word "month" is derived from "moonth", which was how long the moon was observed to take to return to a specific phase.

There are a lot of ways of looking at this depending on your relation to the Earth/moon system. The sight differences occur because the moon and the Earth are both dynamic (moving) systems and the point at which the moon is said to be "in the same position" is slightly different:

1. The Moon's orbital period in a non-rotating frame of reference is 27.32 days (27 days, 7 hours, 43 minutes, 11.6 seconds). This is known as a sidereal month and is measured by observing how long it takes the Moon to pass a fixed star on the celestial sphere.
2. A synodic month is 29.53 days (29 days, 12 hours, 44 minutes, 2.8 seconds) and is measured from New Moon to New Moon. The synodic month is the most common way of expressing the lunar cycle.
3. An anomalistic month is the Moon's orbital period measured from perigee to perigee - the point in the Moon's orbit when it is closest to Earth. An anomalistic month is about 27.55 days on average.
4. The tropical month is the time for the Moon to return to the same ecliptic longitude, i.e. measured from the equinox; it is slightly shorter than the sidereal month because of precession of the equinoxes.
5. The draconic month or nodal month is the period in which the Moon returns to the same node of its orbit; the nodes are the two points where the Moon's orbit crosses the plane of the Earth's orbit. Its duration is about 27.21 days on average.

Answer 2

One week. The moon orbits the earth every 27.3 days (about 4 weeks). As the earth orbits the sun, the moon orbits the earth. Half the time the moon is traveling backwards, and the other half of the time forwards. So from the furthest trailing position, it would take about a week to catch up, then for the next week it would be ahead of the earth (as the earth orbits the sun), reaching the forward most position, then moving back....

When the moon is full, incidentally, is when it has "caught up" with the earth. When it is only half full but growing, that is when it is in its furthest trailing position.

Answer 3

28 days.