How many times does the moon orbit the earth in a year?

Question

is it 13?

That's cool Don, why don't we just use the Mayan calendar then?

Answer 1

Please look at the Chinese lunar calendar.

Answer 2

The Gregorian calendar we use today has 12 months and it came from the Julian calendar created by the Romans back in the day. The idea of the month was based on the phases of the moon. The moon orbits the Earth every 27.3 days, but it's phases repeat every 29.5 or so days. The length of the months were based on this. When the calendar was developed, they wanted each year to be based on the cycle of the seasons, and they wanted each month to be roughly the same length. Since 12 months of alternating 29 and 30 days didn't quite add up to the 365 days of the year, they lengthened the month instead of adding partial months to make it easier. The year contained the following months:

Martius (31 days)
Aprilus (30)
Maius (31)
Junius (30)
Quintilus (31)
Sextilus (30)
September (31)
October (30)
November (31)
December (30)
Januarius (31)
Februarius (29, 30 on leap years)

As you can see, February was at the end of the year and had 29 days. The month of Quintilus was renamed in honor of Julius Caesar to Julius. Later on, the month of Sextilus was renamed for Augustus Caesar. It only had 30 days though, and Julius had 31, so in order to correct this discrepancy, A day was taken from the last month, Februarius, and added to Augustus to give it 31 days. Eventually, the new year was set to begin in Januarius, and after this, the months of September through December shifted days so that the months Julius, Augustus, and September wouldn't have all 31 days in a row.

This is how our calendar ended up as it did. It explains why the alternating 31/30 days breaks between July and August, and why February, which we consider the second month, has only 28 days, and why it gets the leap day.

Answer 3

Very close to 13 times. 13x28 = 364, and the year has 365 days.

You may wonder why we don't have 13 months, then -- some religious calendars such as the Muslim calendar do in fact have 13 months. However, there are AROUND 12 constellations that can be clearly identified with each month, and not a really good 13th one, so folks fell into this whole 12 month thing a while back and sort of got stuck there.

Answer 4

Roughly 12 + 7/19th times. If you check the Jewish religious calendar, it is based on new moon to new moon months, and has in a 19 year cycle 12- 12 month years and 7-13 month years.

Answer 5

12

Answer 6

A moon's cycle is the time the moon takes to change from looking very bright and round to looking very small and thin, and then back to bright and round again. In the case of the Earth's moon, this is about four weeks. It does this about 13 times in one year. The moon's cycle is about 28 days, a bit shorter than a calendar month.

The period of revolution is the SIDEREAL MONTH and has mean value of 27.32166 days. The SYNODICAL MONTH is the interval of time between two identical phases and has a mean value of 29.53059 days.


The Eastward motion of the Moon against the background of stars has a speed of per mean solar day. Thus time intervals between successive Lunar transits, ie. LUNAR DAYS, have a mean duration of 24hr 51min. The Moon changes its position by approximately , or its own angular diameter, per hour.


The Moon's obstruction of other celestial objects is called occultation. The Moon revolves about its axis with exactly the same period that it revolves about the Earth, ie. in a synchronous orbit --and thus presents the same face towards the Earth.

Librations of the Moon are small oscillations from time to time which allow us to get short glimpses of small portions of the side of the Moon which is normally hidden.


The Moon orbits the Earth in an ellipse (a=384,400 km, e=0.0549). The plane of the lunar orbit intersects the ecliptic at an angle of In consequence of perturbations by the Sun and planets the Moon's orbit has two major motions:


(i) The line of nodes of the lunar orbit (the line of intersection of the plane of the lunar orbit with the plane of the ecliptic) has a retrograde motion ie. rotates towards the West (in the plane of the ecliptic) at a rate of /year ie. with a period of 18.60 years (nutation period). Thus the node, or point at which the Moon's orbit crosses the ecliptic, moves steadily Westward. The interval of time between the passage of the Moon through the same node is called the DRACONITIC MONTH, and is 27.2122 days. The times of the eclipses depend upon these factors.


(ii) Perigee is distance of closest approach, apogee is that of farthest. The line joining these two points (the line of Apsides) has a progressive motion, it advances ie. rotates in space in the plane of the Moon's orbit to the East, ie. direct motion, making one complete revolution in 3232.575 days or about 8.85 years

Answer 7

the moon orbits the earth as frequently as the earth revolves around the sun, which is 365 times a year

Answer 8

a little bit over 12 times a year