How long does it take for the moon to orbit the 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.

About once every 28 days, this is the root of why we use months in our calendars.

Inconveniently, since 11 of the 12 months are longer than the moon's cycle of

phases, the months no longer show much correlation with the moon.

The orbit of the Moon around the Earth is completed in approximately 27.32 days. The more precise figure is 27 days, 7 hours, 43 minutes, 11.6 seconds. The period between consecutive phases is longer, at 29.53 days, because the position of the Earth and Moon changes as Earth orbits around the Sun.

There are a number of times related to the orbit of the Moon:

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 the sidereal month. It is measured by observing how long it takes the Moon to pass a fixed star.
2. A synodic month is 29.53 days (29 days, 12 hours, 44 minutes, 2.8 seconds) It is measured from New Moon to New Moon. This 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 dayson 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 (one of 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

Earth and moon orbit their common center of mass every 27.32 days.

Answer 3

It doesn't. The moon orbits the Earth. This happens because the Earth has a bigger gravitational field.

Answer 4

The moon revolves around the earth in a slight ellipse. The revolution takes 27 days, 7 hours, 43 minutes, and 11.6 seconds.

Answer 5

27.32 days