Orbit of the Moon - wikipedia Orbit of the Moon Not to be confused with Lunar orbit ( the orbit of an object around the Moon ). Orbit of the Moon Diagram of the Earth -- Moon system Property Value Semi-major axis 384,748 km ( 239,071 mi ) Mean distance 385,000 km ( 239,000 mi ) Inverse sine parallax 384,400 km ( 238,900 mi ) Perigee ( i.e. min. distance from Earth ) 362,600 km ( 225,300 mi ) ( avg. ) ( 356 400 -- 370 400 km ) Apogee ( i.e. max. distance from Earth ) 405,400 km ( 251,900 mi ) ( avg. ) ( 404 000 -- 406 700 km ) Mean eccentricity 6998549006000000000 ♠ 0.054 9006 ( 0.026 -- 0.077 ) Mean obliquity 6.687 ° Mean inclination of orbit to ecliptic 5.15 ° ( 4.99 -- 5.30 ) of lunar equator to ecliptic 1.543 ° Period of precession of nodes 18.5996 years precession of line of apsides 8.8504 years The Moon orbits Earth in the prograde direction and completes one revolution relative to the stars in approximately 27.323 days ( a sidereal month ). Earth and the Moon orbit about their barycentre ( common center of mass ), which lies about 4,600 km ( 2,900 mi ) from Earth 's center ( about 3 / 4 of the radius of Earth ). On average, the distance to the Moon is about 385,000 km ( 239,000 mi ) from Earth 's centre, which corresponds to about 60 Earth radii. With a mean orbital velocity of 1.022 km / s ( 2,290 mph ), the Moon appears to move relative to the stars each hour by an amount roughly equal to its angular diameter, or by about half a degree. The Moon differs from most satellites of other planets in that its orbit is close to the plane of the ecliptic, and not to Earth 's equatorial plane. The plane of the lunar orbit is inclined to the ecliptic by about 5 °, whereas the Moon 's equatorial plane is inclined by only 1.5 ° to the ecliptic. Contents 1 Properties 1.1 Elliptic shape 1.2 Elongation 1.3 Rotation 1.4 Inclination 1.4. 1 Nodes 1.4. 2 Lunar standstill 1.4. 3 Scale model 2 History of observations and measurements 3 Lunar periods 4 Tidal evolution 5 Libration 6 Path of Earth and Moon around Sun 7 See also 8 References 9 External links Properties The properties of the orbit described in this section are approximations. The Moon 's orbit around Earth has many irregularities ( perturbations ), whose study ( lunar theory ) has a long history. Comparison of the Moon 's apparent size at lunar perigee -- apogee Elliptic shape The orbit of the Moon is distinctly elliptical, with an average eccentricity of 0.0549. The non-circular form of the lunar orbit causes variations in the Moon 's angular speed and apparent size as it moves towards and away from an observer on Earth. The mean angular movement relative to an imaginary observer at the barycentre is 7001131760000000000 ♠ 13.176 ° per day to the east ( Julian day 2000 ). Elongation The Moon 's elongation is its angular distance east of the Sun at any time. At new moon, it is zero and the Moon is said to be in conjunction. At full moon, the elongation is 180 ° and it is said to be in opposition. In both cases, the Moon is in syzygy, that is, the Sun, Moon and Earth are nearly aligned. When elongation is either 90 ° or 270 °, the Moon is said to be in quadrature. Rotation Apsidal precession -- the Moon 's orbit rotates once every 8.85 years. Orbital inclination -- the Moon 's orbit is inclined by 5.14 ° to the ecliptic. Earth 's lunar orbit perturbations The orientation of the orbit is not fixed in space, but rotates over time. This orbital precession is also called apsidal precession and is the rotation of the Moon 's orbit within the orbital plane, i.e. the axes of the ellipse change direction. The Moon 's major axis -- the longest diameter of the orbit, joining its nearest and farthest points, the perigee and apogee, respectively -- makes one complete revolution every 8.85 Earth years, or 3,232.6054 days, as it rotates slowly in the same direction as the Moon itself ( direct motion ). The Moon 's apsidal precession is distinct from, and should not be confused with its axial precession. Inclination The mean inclination of the lunar orbit to the ecliptic plane is 5.145 °. The rotational axis of the Moon is also not perpendicular to its orbital plane, so the lunar equator is not in the plane of its orbit, but is inclined to it by a constant value of 6.688 ° ( this is the obliquity ). This does not mean that, as a result of the precession of the Moon 's orbital plane, the angle between the lunar equator and the ecliptic would vary between the sum ( 11.833 ° ) and difference ( 1.543 ° ) of these two angles, but, as was discovered by Jacques Cassini in 1722, the rotational axis of the Moon precesses with the same rate as its orbital plane, but is 180 ° out of phase ( see Cassini 's Laws ). Therefore, the angle between the ecliptic and the lunar equator is always 1.543 °, even though the rotational axis of the Moon is not fixed with respect to the stars. Because of the inclination of the moon 's orbit, the moon is above the horizon at the North and South Pole for almost two weeks every month, even though the sun is below the horizon for six months at a time. The period from moonrise to moonrise at the poles is quite close to the sidereal period, or 27.3 days. When the sun is the furthest below the horizon ( winter solstice ), the moon will be full when it is at its highest point. Nodes Main article : Lunar node The nodes are points at which the Moon 's orbit crosses the ecliptic. The Moon crosses the same node every 27.2122 days, an interval called the draconic or draconitic month. The line of nodes, the intersection between the two respective planes, has a retrograde motion : for an observer on Earth it rotates westward along the ecliptic with a period of 18.60 years, or 19.3549 ° per year. When viewed from celestial north, the nodes move clockwise around Earth, opposite to Earth 's own spin and its revolution around the Sun. Lunar and solar eclipses can occur when the nodes align with the Sun, roughly every 173.3 days. Lunar orbit inclination also determines eclipses ; shadows cross when nodes coincide with full and new moon, when the Sun, Earth, and Moon align in three dimensions. In effect, this means that the `` tropical year '' on the moon is only 347 days long. This is called the draconic year or eclipse year. The `` seasons '' on the moon fit into this period. For about half of this draconic year, the sun is north of the lunar equator ( but at most 1.543 ° ), and for the other half it is south of the lunar equator. Obviously the effect of these seasons is very minor compared to the difference between lunar night and lunar day. At the poles, there are not days and nights of about 15 Earth days, but rather the sun will be `` up '' for 173 days at a time. `` Up '' here means that the centre of the sun is above the horizon. The sunrise and sunset at the poles each take about 18 days. These polar sunrises and sunsets occur around the time of eclipses ( solar or lunar ). For example, at the Solar eclipse of March 9, 2016, the moon was near its descending node, and the sun was near the point in the sky where the equator of the moon crosses the ecliptic. When the sun reached that point, the centre of the sun set at the north pole and rose at the south pole. Lunar standstill Every 18.6 years, the angle between the moon 's orbit and the Earth 's equator reaches a maximum of 28 ° 36 ′ ( the sum of the Earth 's inclination 23 ° 27 ′ and the Moon 's inclination 5 ° 09 ′ ). This is called major lunar standstill. Around this time, the moon 's latitude will vary from − 28 ° 36 ′ to + 28 ° 36 ′. 9.3 years later, the angle between the moon 's orbit and the Earth 's equator reaches its minimum, 18 ° 20 ′. This is called a minor lunar standstill. When the inclination of the moon 's orbit to the Earth 's equator is at its minimum of 18 ° 20 ′, the centre of the moon 's disk will be above the horizon every day as far north and as far south as 90 ° − 18 ° 20 ' or 71 ° 40 ' latitude, whereas when the inclination is at its maximum of 28 ° 36 ' the centre of the moon 's disk will only be above the horizon every day for latitudes less than 90 ° − 28 ° 36 ' or 61 ° 24 '. At higher latitudes there will be a period of at least a day each month when the moon does not rise, but there will also be a period of at least a day each month during which the moon does not set. This is similar to the behaviour of the sun, but with a period of 27.3 days instead of 365 days. Note that a point on the moon can actually be visible when it is below the horizon by about 34 arc minutes, due to refraction ( see Sunrise ). Scale model Scale model of the Earth -- Moon system : Sizes and distances are to scale. History of observations and measurements About 1000 BC, the Babylonians were the first human civilization known to have kept a consistent record of lunar observations. Clay tablets from that period, which have been found over the territory of present - day Iraq, are inscribed with cuneiform writing recording the times and dates of moonrises and moonsets, the stars that the Moon passed close by, and the time differences between rising and setting of both the Sun and the Moon around the time of the full moon. Babylonian astronomy discovered the three main periods of the Moon 's motion and used data analysis to build lunar calendars that extended well into the future. This use of detailed, systematic observations to make predictions based on experimental data may be classified as the first scientific study in human history. However, the Babylonians seem to have lacked any geometrical or physical interpretation of their data, and they could not predict future lunar eclipses ( although `` warnings '' were issued before likely eclipse times ). Ancient Greek astronomers were the first to introduce and analyze mathematical models of the motion of objects in the sky. Ptolemy described lunar motion by using a well - defined geometric model of epicycles and evection. Isaac Newton was the first to develop a complete theory of motion, mechanics. The sheer wealth of humanity 's observations of the lunar motion was the main testbed of his theory. Lunar periods See also : Lunar month and Month Name Value ( days ) Definition Sidereal month 7001273216620000000 ♠ 27.321 662 with respect to the distant stars ( 13.36874634 passes per solar orbit ) Synodic month 7001295305890000000 ♠ 29.530 589 with respect to the Sun ( phases of the Moon, 12.36874634 passes per solar orbit ) Tropical month 7001273215820000000 ♠ 27.321 582 with respect to the vernal point ( precesses in ~ 26,000 years ) Anomalistic month 7001275545500000000 ♠ 27.554 550 with respect to the perigee ( precesses in 3232.6054 days = 8.850578 years ) Draconic month 7001272122210000000 ♠ 27.212 221 with respect to the ascending node ( precesses in 6793.4765 days = 18.5996 years ) There are several different periods associated with the lunar orbit. The sidereal month is the time it takes to make one complete orbit around Earth with respect to the fixed stars. It is about 27.32 days. The synodic month is the time it takes the Moon to reach the same visual phase. This varies notably throughout the year, but averages around 29.53 days. The synodic period is longer than the sidereal period because the Earth -- Moon system moves in its orbit around the Sun during each sidereal month, hence a longer period is required to achieve a similar alignment of Earth, the Sun, and the Moon. The anomalistic month is the time between perigees and is about 27.55 days. The Earth -- Moon separation determines the strength of the lunar tide raising force. The draconic month is the time from ascending node to ascending node. The time between two successive passes of the same ecliptic longitude is called the tropical month. The latter three periods are slightly different from the sidereal month. The average length of a calendar month ( a twelfth of a year ) is about 30.4 days. This is not a lunar period, though the calendar month is historically related to the visible lunar phase. The Moon 's distance from Earth and moon phases in 2014. Moon phases : 0 ( 1 ) -- new moon, 0.25 -- first quarter, 0.5 -- full moon, 0.75 -- last quarter Tidal evolution See also : Tide, Tidal acceleration, and Axial tilt § Long term The gravitational attraction that the Moon exerts on Earth is the cause of tides in the sea ; the Sun has a lesser tidal influence. If Earth had a global ocean of uniform depth, the Moon would act to deform both the solid Earth ( by a small amount ) and the ocean in the shape of an ellipsoid with the high points roughly beneath the Moon and on the opposite side of Earth. However, because of the presence of the continents, Earth 's much faster rotation and varying ocean depths, this simplistic visualisation does not happen. Although the tidal flow period is generally synchronized to the Moon 's orbit around Earth, its relative timing varies greatly. In some places on Earth, there is only one high tide per day, whereas others have four, though this is somewhat rare. The notional tidal bulges are carried ahead of the Earth -- Moon axis by the continents as a result of Earth 's rotation. The eccentric mass of each bulge exerts a small amount of gravitational attraction on the Moon, with the bulge on the side of Earth closest to the Moon pulling in a direction slightly forward along the Moon 's orbit ( because Earth 's rotation has carried the bulge forward ). The bulge on the side furthest from the Moon has the opposite effect, but because the gravitational attraction varies inversely with the square of distance, the effect is stronger for the near - side bulge. As a result, some of Earth 's angular ( or rotational ) momentum is gradually being transferred to the rotation of the Earth -- Moon pair around their mutual centre of mass, called the barycentre. This slightly faster rotation causes the Earth -- Moon distance to increase at approximately 38 millimetres per year. Conservation of angular momentum means that Earth 's axial rotation is gradually slowing, and because of this its day lengthens by approximately 23 microseconds every year ( excluding glacial rebound ). Both figures are valid only for the current configuration of the continents. Tidal rhythmites from 620 million years ago show that, over hundreds of millions of years, the Moon receded at an average rate of 22 mm ( 0.87 in ) per year and the day lengthened at an average rate of 12 microseconds per year, both about half of their current values. See tidal acceleration for a more detailed description and references. The Moon is gradually receding from Earth into a higher orbit, and calculations suggest that this would continue for about 50 billion years. By that time, Earth and the Moon would be in a mutual spin -- orbit resonance or tidal locking, in which the Moon will orbit Earth in about 47 days ( currently 27 days ), and both the Moon and Earth would rotate around their axes in the same time, always facing each other with the same side. This has already happened to the Moon -- the same side always faces Earth -- and is also slowly happening to the Earth. However, the slowdown of Earth 's rotation is not occurring fast enough for the rotation to lengthen to a month before other effects change the situation : approximately 2.3 billion years from now, the increase of the Sun 's radiation will have caused Earth 's oceans to evaporate, removing the bulk of the tidal friction and acceleration. Libration Main article : Libration Animation of the Moon as it cycles through its phases. The apparent wobbling of the Moon is known as libration. The Moon is in synchronous rotation, meaning that it keeps the same face toward Earth at all times. This synchronous rotation is only true on average, because the Moon 's orbit has a definite eccentricity. As a result, the angular velocity of the Moon varies as it orbits Earth and hence is not always equal to the Moon 's rotational velocity. When the Moon is at its perigee, its rotation is slower than its orbital motion, and this allows us to see up to eight degrees of longitude of its eastern ( right ) far side. Conversely, when the Moon reaches its apogee, its rotation is faster than its orbital motion and this reveals eight degrees of longitude of its western ( left ) far side. This is referred to as longitudinal libration. Because the lunar orbit is also inclined to Earth 's ecliptic plane by 5.1 °, the rotational axis of the Moon seems to rotate towards and away from Earth during one complete orbit. This is referred to as latitudinal libration, which allows one to see almost 7 ° of latitude beyond the pole on the far side. Finally, because the Moon is only about 60 Earth radii away from Earth 's centre of mass, an observer at the equator who observes the Moon throughout the night moves laterally by one Earth diameter. This gives rise to a diurnal libration, which allows one to view an additional one degree 's worth of lunar longitude. For the same reason, observers at both of Earth 's geographical poles would be able to see one additional degree 's worth of libration in latitude. Path of Earth and Moon around Sun Section of the Earth -- Moon system 's trajectory around the Sun ( to scale ) orbital path of the Earth orbital path of the Moon When viewed from the north celestial pole, i.e. from the approximate direction of the star Polaris, the Moon orbits Earth anticlockwise and Earth orbits the Sun anticlockwise, and the Moon and Earth rotate on their own axes anticlockwise. The right - hand rule can be used to indicate the direction of the angular velocity. If the thumb of the right hand points to the north celestial pole, its fingers curl in the direction that the Moon orbits Earth, Earth orbits the Sun, and the Moon and Earth rotate on their own axes. In representations of the Solar System, it is common to draw the trajectory of Earth from the point of view of the Sun, and the trajectory of the Moon from the point of view of Earth. This could give the impression that the Moon orbits Earth in such a way that sometimes it goes backwards when viewed from the Sun 's perspective. Because the orbital velocity of the Moon around Earth ( 1 km / s ) is small compared to the orbital velocity of Earth about the Sun ( 30 km / s ), this never happens. There are no rearward loops in the Moon 's solar orbit. Considering the Earth -- Moon system as a binary planet, its centre of gravity is within Earth, about 4,624 km ( 2,873 mi ) or 72.6 % of the Earth 's radius from the centre of the Earth. This centre of gravity remains on the line between the centres of the Earth and Moon as the Earth completes its diurnal rotation. The path of the Earth -- Moon system in its solar orbit is defined as the movement of this mutual centre of gravity around the sun. Consequently, Earth 's centre veers inside and outside the solar orbital path during each synodic month as the Moon moves in its orbit around the common centre of gravity. The Sun 's gravitational effect on the Moon is more than twice that of Earth 's on the Moon ; consequently, the Moon 's trajectory is always convex ( as seen when looking Sunward at the entire Sun -- Earth -- Moon system from a great distance outside Earth -- Moon solar orbit ), and is nowhere concave ( from the same perspective ) or looped. That is, the region enclosed by the Moon 's orbit of the Sun is a convex set. See also Moon portal Ernest William Brown Double planet List of orbits ELP2000 Ephemeris Jet Propulsion Laboratory Development Ephemeris Lunar distance ( astronomy ) Lunar Laser Ranging Experiment Lunar phase Lunar theory Milankovitch cycles Orbital elements Supermoon References Jump up ^ The geometric mean distance in the orbit ( of ELP ) Jump up ^ M. Chapront - Touzé ; J. Chapront ( 1983 ). `` The lunar ephemeris ELP - 2000 ''. Astronomy & Astrophysics. 124 : 54. Bibcode : 1983A&A... 124... 50C. Jump up ^ The constant in the ELP expressions for the distance, which is the mean distance averaged over time Jump up ^ M. Chapront - Touzé ; J. Chapront ( 1988 ). `` ELP2000 - 85 : a semi-analytical lunar ephemeris adequate for historical times ''. Astronomy & Astrophysics. 190 : 351. Bibcode : 1988A&A... 190... 342C. Jump up ^ This often quoted value for the mean distance is actually the inverse of the mean of the inverse of the distance, which is not the same as the mean distance itself. ^ Jump up to : Jean Meeus, Mathematical astronomy morsels ( Richmond, VA : Willmann - Bell, 1997 ) 11 -- 12. Jump up ^ Lang, Kenneth R. ( 2011 ), The Cambridge Guide to the Solar System, 2nd ed., Cambridge University Press. Jump up ^ `` Moon Fact Sheet ''. NASA. Retrieved 2014 - 01 - 08. ^ Jump up to : Martin C. Gutzwiller ( 1998 ). `` Moon - Earth - Sun : The oldest three - body problem ''. Reviews of Modern Physics. 70 ( 2 ) : 589 -- 639. Bibcode : 1998RvMP... 70... 589G. doi : 10.1103 / RevModPhys. 70.589. Jump up ^ `` View of the Moon ''. U. of Arkansas at Little Rock. Retrieved May 9, 2016. Jump up ^ Calculated from arcsin ( 0.25 ° / 1.543 ° ) / 90 ° times 173 days, since the angular radius of the sun is about 0.25 °. Jump up ^ The periods are calculated from orbital elements, using the rate of change of quantities at the instant J2000. The J2000 rate of change equals the coefficient of the first - degree term of VSOP polynomials. In the original VSOP87 elements, the units are arcseconds ( '' ) and Julian centuries. There are 1,296,000 '' in a circle, 36525 days in a Julian century. The sidereal month is the time of a revolution of longitude λ with respect to the fixed J2000 equinox. VSOP87 gives 1732559343.7306 '' or 1336.8513455 revolutions in 36525 days -- 27.321661547 days per revolution. The tropical month is similar, but the longitude for the equinox of date is used. For the anomalistic year, the mean anomaly ( λ - ω ) is used ( equinox does not matter ). For the draconic month, ( λ - Ω ) is used. For the synodic month, the sidereal period of the mean Sun ( or Earth ) and the Moon. The period would be 1 / ( 1 / m - 1 / e ). VSOP elements from Simon, J.L. ; Bretagnon, P. ; Chapront, J. ; Chapront - Touzé, M. ; Francou, G. ; Laskar, J. ( February 1994 ). `` Numerical expressions for precession formulae and mean elements for the Moon and planets ''. Astronomy and Astrophysics. 282 ( 2 ) : 669. Bibcode : 1994A&A... 282... 663S. Jump up ^ Jean Meeus, Astronomical Algorithms ( Richmond, VA : Willmann - Bell, 1998 ) p 354. From 1900 -- 2100, the shortest time from one new moon to the next is 29 days, 6 hours, and 35 min, and the longest 29 days, 19 hours, and 55 min. Jump up ^ C.D. Murray ; S.F. Dermott ( 1999 ). Solar System Dynamics. Cambridge University Press. p. 184. Jump up ^ Dickinson, Terence ( 1993 ). From the Big Bang to Planet X. Camden East, Ontario : Camden House. pp. 79 -- 81. ISBN 0 - 921820 - 71 - 2. Jump up ^ Caltech Scientists Predict Greater Longevity for Planets with Life ^ Jump up to : The reference by H.L. Vacher ( 2001 ) ( details separately cited in this list ) describes this as ' convex outward ', whereas older references such as `` The Moon 's Orbit Around the Sun, Turner, A.B. Journal of the Royal Astronomical Society of Canada, Vol. 6, p. 117, 1912JRASC... 6... 117T '' ; and `` H Godfray, Elementary Treatise on the Lunar Theory '' describe the same geometry by the words concave to the sun. ^ Jump up to : Aslaksen, Helmer ( 2010 ). `` The Orbit of the Moon around the Sun is Convex ! ''. Retrieved 2006 - 04 - 21. Jump up ^ The Moon Always Veers Toward the Sun at MathPages Jump up ^ Vacher, H.L. ( November 2001 ). `` Computational Geology 18 -- Definition and the Concept of Set '' ( PDF ). Journal of Geoscience Education. 49 ( 5 ) : 470 -- 479. Retrieved 2006 - 04 - 21. External links View of the Moon Good diagrams of Moon, Earth, tilts of orbits and axes, courtesy of U. of Arkansas The Moon Physical features Face on the Moon Internal structure Gravity field Topography Magnetic field Atmosphere Ion tail Moonlight Lunar swirls Orbit Orbit of the Moon Phases Lunation Lunar libration Full Moon Lunar terminator Full moon cycle Earthshine Lunar eclipse Solar eclipse Solar eclipses on the Moon Tide Surface Selenography Near side Far side North pole South pole Lunar mare List Craters List Calderas Mountains Valleys Volcanic features South Pole -- Aitken basin Shackleton crater Water Soil Ray systems Peak of eternal light Crater of eternal darkness Space weathering Transient lunar phenomenon Lunar basalt 70017 Science Geology timescale Giant - impact hypothesis Hill sphere Moon rocks Lunar meteorites KREEP Late Heavy Bombardment Lunar laser ranging ALSEP Observation Origin Lunar sample displays Apollo 11 lunar sample display Apollo 17 lunar sample display Exploration Apollo program Exploration of the Moon Colonization of the Moon List of lunar probes List of missions to the Moon Moon landing conspiracy theories Related topics Lunar calendar Lunisolar calendar Craters named after people Double planet Lunar effect Man in the Moon Memorials on the Moon Month Lunar month Moon illusion Harvest moon Hunter 's moon Moon in art and literature Moon in mythology Hjúki and Bil ( Norse legends ) Moon is made of green cheese Natural satellite Solar System Supermoon Theia Tourism Phases / Occurrence Black moon Blue moon Lunar phase New moon Dark moon Wet moon Lilith ( hypothetical moon ) Moon portal Earth sciences portal Solar System portal Earth 's location in the Universe Included Earth → Solar System → Local Interstellar Cloud → Local Bubble → Gould Belt → Orion Arm → Milky Way → Milky Way subgroup → Local Group → Virgo Supercluster → Laniakea Supercluster → Observable universe → Universe Each arrow ( → ) may be read as `` within '' or `` part of ''. Related Cosmic View ( 1957 essay ) To the Moon and Beyond ( 1964 film ) Cosmic Zoom ( 1968 film ) Powers of Ten ( 1968 and 1977 films ) Cosmic Voyage ( 1996 documentary ) Cosmic Eye ( 2012 ) Astronomy portal - Cosmology portal Gravitational orbits Types General Box Capture Circular Elliptical / Highly elliptical Escape Graveyard Hyperbolic trajectory Inclined / Non-inclined Osculating Parabolic trajectory Parking Synchronous semi sub Transfer orbit Geocentric Geosynchronous Geostationary Sun - synchronous Low Earth Medium Earth High Earth Molniya Near - equatorial Orbit of the Moon Polar Tundra About other points Areosynchronous Areostationary Halo Lissajous Lunar Heliocentric Heliosynchronous Parameters Shape Size e Eccentricity a Semi-major axis b Semi-minor axis Q, q Apsides Orientation i Inclination Ω Longitude of the ascending node ω Argument of periapsis π Longitude of the periapsis Position M Mean anomaly ν True anomaly E Eccentric anomaly L Mean longitude l True longitude Variation T Orbital period n Mean motion v Orbital speed t Epoch Maneuvers Collision avoidance ( spacecraft ) Delta - v Delta - v budget Bi-elliptic transfer Geostationary transfer Gravity assist Gravity turn Hohmann transfer Low energy transfer Oberth effect Inclination change Phasing Rocket equation Rendezvous Transposition, docking, and extraction Orbital mechanics Celestial coordinate system Characteristic energy Escape velocity Ephemeris Equatorial coordinate system Ground track Hill sphere Interplanetary Transport Network Kepler 's laws of planetary motion Lagrangian point n - body problem Orbit equation Orbital state vectors Perturbation Retrograde motion Specific orbital energy Specific relative angular momentum Two - line elements List of orbits Retrieved from `` https://en.wikipedia.org/w/index.php?title=Orbit_of_the_Moon&oldid=800854365 '' Categories : Orbit of the Moon Talk Contents About Wikipedia Беларуская Català Deutsch Español فارسی Français 한국어 Հայերեն Italiano 日本 語 Polski Português Русский Svenska Українська اردو 中文 Edit links This page was last edited on 16 September 2017, at 02 : 32. 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Question: who discovered that the moon orbits the earth
Answer: the Babylonians