of the titles of this article is ambiguous. For further meanings see moon (term clarifying).
Im Weltraum erscheint der Mond als graue Kugel, die von Kratern unterschiedlicher Größe übersäht ist.
farthest-from-Earth point 406,740 km
middle course radius 384,405 km
nearest-to-Earth point 356,410 km
numeric eccentricity 0.0549
scan time
(Sideri month)
27 D 7 h 43,7m
27.32166 days
Synodi month 29.53059 days
tropical period 27.32158 days
Drakoniti period 27.21222 days
of anomaly tables period 27.55455 days
Sarosperiode 18 years 11.3 days
Metoni cycle 19 trop. J 2 h
Ø orbital speed of 1.03 km/s
flight path angle 5,1454°
is more natural Satellite of the earth
physical characteristics
of equatorial diameters 3,476 km
surface 37.9 millions km 2
mass 7,348 · 10 22 kg
(1/81 of the earth mass)
middle one density 3.345 g/cm 3
surface acceleration 1.62 m/s 2
rotation duration 27 D 07 h 43.7 m
inclinationthe rotation axle 1,5424°
Mittl. spherical albedo
Mittl. geometrical albedo
escape velocity 2.38 km/s
surface temperature in °C
min. mittl. max.
-143 -23 +127
traces of an atmosphere
air pressure 3 · 10 −10 Pa
helium 25%
neon 25%
hydrogen 23%
argon 20%

carbon dioxide

composition of the moon crust
oxygen 43%
silicon 21%
aluminum 10%
calcium 9%
iron 9%
magnesium 5%
titanium 2%
nickel 0.6%
sodium 0.3%
chrome 0.2%
potassium 0.1%
manganese 0.1%
sulfur 0.1%
phosphorus 500 ppm
carbon 100 ppm
nitrogen 100 ppm
hydrogen 50 ppm
helium 20 ppm

the moon (Latin Luna), which only moon is usually called, is the only onenatural satellite of the earth. It is the only strange heavenly body, which became to enter so far from humans, and concomitantly the best investigated. Nevertheless he saves still many secrets, approximately to his emergence and some land forms. Thoselater development and its internal structure are however clarified for some years to a large extent.

The usual indication of the moon is the removing, from the terrestrial Northern Hemisphere regarded Mondsichel: ☾

Table of contents

course andRotation of the moon

apparent movement from the earth seen

the moon circles the earth in the process of approx. 29.5 days of the west eastward. Because of the rotation of the earth around itself it circles however apparently the earth inabout 24 hours and 50 minutes from the east to the west. The course of the moon is bent around 5,1 degrees against the sun course. Its apparent movement resembles thereby that the sun.

The time of the moon up and - fall is therebyeach day about 50 minutes later. In 29 days the moon 28 times comes up. For an observer in the Northern Hemisphere the moon (like also the sun) at its highest point of course stands in the south, for an observer on the Southern Hemispherein the north (and the visible surface textures appear posed in the comparison to the Northern Hemisphere on the head). Into near-equator ones one can see the moon at its highest point in the zenith.


the course of the moon around the earth is an ellipse the numeric eccentricity 0,055; that is, the largest and the smallest distance of the center deviate in each case by 5,5 per cent from a real circular path. The middle course radius - the large shaft section - measures 384,400 kilometers. The nearest-to-Earth point of the courseone calls perigee. It is 356,410 km far away from the earth center. The farthest-from-Earth point is called apogee and is 406,740 km far away from the earth center. One calls the passages of the moon by the course level of the earth (the ecliptic) moon knots (orPoints of kite), whereby the ascending knot the entrance into the north, which describes descending into the south hemisphere.

The moon rotates the sun together with the earth, by the movement around the earth oscillates the moon however around a common elliptical orbit.The variation of the gravitation during this oscillating motion leads together with smaller disturbances by the other planets to deviations from an accurate Keplerellipse around the earth.

  • The perigee rotates the earth directly with one period of 8.85 years.
  • The moon knots rotatethe earth due to a precession movement retrograd, thus against the direction of rotation of the moon, with one period of 18.61 years. They cause therefore a weak modulation of the earth precession with evenly this period, which is called Nutation.

Course period

the duration oneCourse circulation of the moon (month) one can specify according to different criteria, which cover different in each case aspects.

  • After a siderischen month (27.32 D) the moon takes again the same position to the fixed stars (from the earth observes).
  • After a synodischen month (29.53 D; Period of the Mondphasen) achieves the moon again the same position to the sun (from the earth observes).
  • It needs a drakonitischen month (27.2122 D), in order to run again by the same knot of its course;it is important for the sunning and lunar eclipses.
  • The moon from a perigee passage needs a abnormalistic month (27.555 D) to the next.


the appearance of the moon varied in the course of his course circulation and goes through the Mondphasen:

The Mondphasen ofNeumond over full moon to Neumond
  • Neumond (1) - the moon stands for the sun and the earth increasing
  • moon ( 2-4) between (in the evening visibly)
  • full moon (5) - the earth stands between the sun and the moon
  • removing moon (6-8) (in the morning visibly)
  • that Halbmond - increasingly (3) or removing (7) - is the half phase (dichotomy).

The parts to earthturn of the moon side not lit up by the sun are never completely dark thereby, but become by the earth light - the Widerschein of the earth's surface andthe terrestrial atmosphere - indirectly a little lightened. This clarification is called also aschgraues moon light and is with narrow Mondsichel to be seen best.

Its cause was already recognized correctly by Leonardo da Vinci. With binoculars small enlargementeven details are recognizable in the earth light, because due to the larger diameter and the higher abilityability ability (=Albedo) of the earth „the full earth is approximately 50 times as bright “as the full moon. Measurements of the aschgrauen moon light permit conclusions on changes groundatmosphere.

The back of the moon is naturally not always dark. With Neumond it lies in the bright sunlight.

Moon rotation

by the tidal effect, which results from the gravitation of the earth, adapted the moon its rotation of the scan time (siderischer month)(bound rotation), i.e., with a circulation he turns in the same direction of rotation once around the own axle. Therefore always the same side is to be seen by the earth from. Due to of dear ration movements and by utilization of the parallaxare from the earth approx. 59% of the lunar surface observably. The back of the moon could be observed 1959 for the first time by space probes.

Because of the bound rotation an observer on the moon always became the earth in the same place of the skysee (apart from easy fluctuations, which are caused by Librationen). The earth thus never goes down „on “or „“. An observer on the moon back can never see the earth against it. Because of the absence of an atmosphere the moon sky is not colored, butblack.One can see stars only at night however also on the moon, or if one against the environment shields the eyes, because the luminous sensivity of the human eye adjusts themselves to the brightly shining lunar surface and knows the stars notmore notice. The earth appears as bluish disk, nearly four times as largely as the moon from the earth. The earth phases are gone through in a synodischen month and are opposite the Mondphasen. With Neumond „full earth prevails “and with full moon „to new earth “.

The sun moves from the moon seen very slowly over the starlit sky. From sunrise to the highest level of the sun it takes one week, and from there a further week up to the sunset, on which a night every fourteen days follows. A day night cycle upthe moon takes thus one month.


darkenings between sun, moon and earth arises, if the three heavenly bodies are on a line, i.e., only with full moon or Neumond, and if itself the moon in one of the two moon knotsfinds. Happens only two times per year.

Lunar eclipse

with a lunar eclipse, which can occur only with full moon, stands the earth between sun and moon. She can be observed on the entire Nachtseite of the earth and lasts maximally 3Hours 40 minutes. One differentiates between

  • total lunar eclipse, with which the moon moves completely into the Erdschatten. The Totalität takes at the most 100 minutes. If one regards geometrical conditions with a total lunar eclipse, then the moon should lie in the Kernschatten of the earth,that theoretically scarcely 1.4 million kilometers into the area to extend should, actually however because of the strong dispersion by the terrestrial atmosphere only about 250,000 kilometers far is enough. The moon is not completely colluded therefore also with total darkness. There thoseTerrestrial atmosphere the blue portions of the sunlight more strongly strews as the red, appears the moon with total darkness than dark red-brown disk; therefore also the occasional designation “blood moon”.
  • partial lunar eclipse, with only one part of the moon of the earth shadedbecomes, i.e. a part of the moon remains visible during the entire process of the darkness.
  • Penumbra darkness, with which the moon only dives (totally or partly) into the penumbra of the earth. Penumbra darkness is rather inconspicuous; it shows up only oneeasy having a horror of that moon side, which is next the Kernschatten of the earth.

Seen from the moon a lunar eclipse presents itself as solar eclipse. The sun behind the black earth disk disappears. With a total lunar eclipse prevails on the whole moon fronttotal solar eclipse, with a partial lunar eclipse is total the solar eclipse on the moon only in some areas, and with a penumbra lunar eclipse partial solar eclipse prevails on the moon. There is circular sun darkness on the moon because of in relation to the sunmuch larger apparent diameter of the earth disk not; only by described light scattering in the terrestrial atmosphere the edge of the black disk becomes a copper-red resplendent ring, which lends the appropriate color to the moon.

Solar eclipse

with a solar eclipse, onlywith Neumond to arise, stands the moon between sun and earth can. She can be observed only in the areas, the core or penumbra of the moon go through; these areas place themselves usually as for a long time, but quite narrow strips on thatEarth's surface. One differentiates:

  • total solar eclipse, with which the moon covers the sun disk some minutes long completely and which earth the Kernschatten (Umbra) of the moon goes through;
  • partial solar eclipse, with which the moon covers the sun disk not completely; thatObserver is thereby in the penumbra (Penumbra) of the moon;
  • circular solar eclipse, if the moon not completely covers by to large Erdferne the sun disk (see also: Passage).


already the Chaldäern was (over approx. 1000 v. Chr. ?)it admits that itself darkness after one period of 18 years and 11 days, which Sarosperiode, repeat. After 223 synodischen and/or. 242 drakonitischen months (of lat. draco, Drache, old astrological symbol for the moon knots, there one there onemoon and sun-corrosive kite assumed) exists again nearly the same position of sun, earth and moon to each other, so that a darkness position results again after 18 years and 11.33 days.

The cause of this period lies in the fact justified that with oneDarkness both the sun and the moon the close knot of the Mondbahn to lie must, which runs in 18 years once around the earth.Thales has this period, which he became acquainted with with a Orientreise, for its darkness prognosis 585 v. Chr.used. By it the Greeks could defeat the militarily superior Perser.

Since the agreement is not accurate the 223/242 months, the Sarosperiode tears about every 1,300 years off and a new does not begin itself, in that the previous darkness any longerrepeat.

Selenologie and Selenografie

the moon to 30. December 2004

the Selenologie or „geology of the moon “concerns itself with its emergence, its structure and its development as well as with the emergence of the observed structures and for it the responsible persons of processes, duringthe task of the Selenografie in the production of moon maps exists.

Characteristics and development of the moon

major item: Emergence of the moon

the moon has a diameter of 3.476 km and exhibits with 3,345 g/cm 3 a smaller density than the earth.Due to its size difference to its planet, quite small compared with other moons, one designates earth and moon occasionally also than double planet. Its middle density small in the comparison to the earth remained also for a long time unsettled and provided for numerous theoriesto the emergence of the moon.

Today the model for the emergence of the moon, recognized far away, means that approximately 4.5 billion years ago a heavenly body of the size Mars almost touching with the earth collided. Much subject became, predominantly outthe earth's crust and the coat of the hitting body, into an earth orbit hurled, clumped there together and formed finally the moon. After current Simulationen formed the moon at a distance of approximately three to five Erdradien, thus in oneHeight between 20.000 and 30,000 kilometers. This was melted and covered by the collision and the freed gravitation energy with the formation of the moon completely by an ocean from magma. In the course of the cooling a crust from the easier formedMinerals out, which are to be found this very day in the high countries. On earth the Pacific is regarded partly than remnants of this event.

„The young “ moon crust became with larger impacts to pierce again and again, so that from the coat new lava inthe developing Krater to follow knew. Educated themselves Maria, which only some hundred million years cooled off later completely. The so-called. „Large bombardments “ended only before 3,8 to 3.2 billion years, after the number of meteorite impacts before approximately 3,9Billions had decreased/gone back years clearly. Afterwards no strong volcanic activity is provable, but could observe some astronomers isolated Leuchterscheinungen.

In November 2005 an international researcher team of the ETH Zurich knew as well as the Universities of Münster, Cologne and Oxford for the first time the birth of theMoon precisely date. But the scientists used an analysis of the isotope tungsten -182 and computed the age of the moon on (4527 ± 10) millions years.

Internal structure of the moon

Schematischer Aufbau des Mondes (links: Vorderseite, rechts: Rückseite)
schematic structure of the moon (left: Front, right: Back)
structure of the outsideLayers of the moon; KREEP: Potassium, rare Earth of element (D. h. Rare ground connection), phosphorus

our knowledge about the structure of the moon is based essentially on the data of the four Seismometer left by the Apollo missions, the various moon quake and vibrations through Meteorite impacts noted, as well as by the Clementine - and lunar the Prospector - mission to the mapping of the surface, the gravitational field and the mineral composition.

The moon possesses 70 (at the moon front) to 150 km (back) thick a crust, of severalMeters thicken Regolithschicht are covered. Among them a firm coat from basalt rocks lies. There are signs for an unsteadiness surface to 500 kilometers depth, at which a change of the rock composition could be present. The 200 to 400 kilometers large eisenhaltige core might Temperatures around 1.600 degrees Celsius exhibit.

The bound rotation of the moon has also influences on form and internal structure. The moon pulled toward earth long and its center of mass lies about 2 kilometers more near to the earth than its geometricalCenter.

Moon quake

of the passive seismic experiment (PSE) (Apollo 11, NASA)

the left Seismometer of the Apollomissionen register about 500 moon quake per year. Quake are very weak compared with terrestrial quake, the strongest reached a strength of scarcely 5 on that Are appropriate for judge scale, most however with a strength of 2. The seismic waves that quake can be pursued until four hours long, become them in the moon inside thus only very weakly absorbed.

More than half that quakedevelop in a depth from 800 to 1,000 kilometers and exhibit frequency points with the apogee - and perigee - for passage, i.e. every 14 days. Also are well-known quake from the region near the surface of the moon. The cause lies in the fact that itselfthe structure of the moon the average value of the gravitation caused by the earth adapted. The internal tensions are diminished by quake, which reach their maximum at the nearest-to-Earth and farthest-from-Earth point of the Mondbahn. The origin that quake does not distribute itselfevenly over a complete coat bowl, but for most quake develop in only about 100 places, which are few kilometers large only in each case. The reason for this concentration is not well-known yet.


Das Gravitationsfeld des Mare Serenitatis (unten) sowie die Topographie (oben), das Mascon ist im Zentrum deutlich zu erkennen (NASA)
the gravitational field of the Mare Serenitatis (down) as well as thoseTopography (above), the Mascon is in the center to recognize clearly (NASA)

by unusual influences on the courses of the lunar orbiter missions received one end of the 1960er first referring to Schwereanomalien, which one called Mascons (Mas s con cent ration, mass concentrations).These anomalies were examined by lunar Prospector more near, them are usually in the center of the Krater and probably by the impacts developed. Possibly it concerns the iron-rich cores of the Impaktoren, those due to the progressive cooling of the moonno more up to the core to drop could not. According to another theory it could concern lava blisters, which ascended as consequence of an impact from the coat.

Lunar surface

the surface of the moon is almost complete from a dry, aschgrauen Staubschicht,the Regolith, covered, the apparent „silver gloss “a terrestrial observer by the contrast to the night sky only one pretends - in reality the moon has even a particularly small albedo (reflecting ability).

The lunar surface shows chain mountains, ditches and grooves (Fossa),flatten cathedrals and large magma levels, however no active tectonics like the earth.


the moon does not possess a considerable atmosphere, therefore meteorites of each size without previous deceleration on the surface constantly hit and pulverize the rocks. By this processdeveloping Regolith covered up to the young Krater the entire surface with several meters a thick layer, which hides the detail structure of the underground. This surface layer makes the investigation more difficult of the structures and their exact developing history substantially.

The Regolith essentially developsfrom the normal surface material, but he has also admixtures, which were shipped by impacts to the respective position. Although it is generally called Mondstaub, the Regolith corresponds rather to a sand layer. The grain size is enough from dust grain size directly at the surfaceover Sandkörner a little more deeply up to stones and rock, which were added only later and not yet completely grind are. A further important component are small glassy Erstarrungsprodukte of impacts. In some places the Regolith exists nearly to the half outthis Agglutinaten, i.e. glass balls, which contain substantial components of the normal mineral Regoliths. They develop, if the melted Impaktprodukte solidifies only after the impact the Regolithschicht.

In moon meteorites the Dhofar 280, that in the year 2001 in Oman foundbecame, new iron - silicon - mineral phases were identified. One of these mineral phases (Fe 2 SI), which thereby in nature clearly was for the first time proven, after the researcher Bruce Hapke as Hapkeit one designated. Bruce Hapke had those into the 1970ernEmergence of such Eisen-Verbindungen by space erosion (English. Space Weathering) predicted. Space erosion is responsible to the surface of atmosphereless bodies for the temporal change particularly also the optical characteristics (reflexivity).

The moon does not have a considerable magnetic field, D. h. the particles of the solar wind- above all hydrogen, helium, neon, carbon and nitrogen - hit on the lunar surface and in the Regolith are implantiert almost unhindered, similarly the ion implantation, which is used in science and technology. In this way formsthe moon Regolith a kind „climate “- archives of the solar wind, comparably the glaciers in Greenland and the Antarctic for the terrestrial climate. In addition it comes still that the cosmic radiation penetrates about a meter deeply into the lunar surface and there by nuclear reactions (main Spallationsreaktionen) new elements to be formed. Consequence of the fact is that rocks of the Mondregoliths z. B. importantly more noble gases contain as terrestrial rocks or also than meteorites from the Asteroidengürtel. In particular the 3 He could a daily for fusion power stations even economicallybecome important.

Since the Mondregolith is from time to time rolled over by impacts, to have the individual components usually a complex irradiation history behind itself. One can often find out however by radiometric dating methods for moon samples, at which time this directly or close thatSurface were and the cosmic radiation and the solar wind were suspended. Thus realizations over the cosmic radiation and the solar wind can be won at these times. (See also: Jumping well theory)


Mare Imbrium with the large Kopernikuskrater at the upper contour(Apollo 17, NASA)

one regarded the dark lowlandses of the moon front, which cover 16 per cent of the lunar surface, in former times as seas. They are therefore called after Giovanni Riccioli Maria ( singular Mare). They consist of 3,1 to 3.8 billion years olddark basalts, only few Krater exhibit and are from 2 to 8 meters thicken Regolithschicht covered, which is rich at iron and magnesium. They probably resulted from large impacts in the early phase of the moon. There in thisDevelopment stage the coat was still liquid, is afterwards filled with lava from the inside it.(See also: Maria of the moon)

Maria, with exception of the Krater, only very small differences in height of maximally 100 meters exhibit list. Toothe Dorsa (back) belongs to these collections, flat upbulging over several dozen the kilometers extends.


the high countries were regarded in former times as continents and are therefore called Terrae. They exhibit clearly more Krater than Maria and becomefrom one to 15 meters thicken Regolithschicht covered, which is rich at bright aluminum-rich Anorthosit. They are selenologisch older than Maria, the examined rocks on 3,8 until approximately 4.5 billion years were dated and are probably the remaindersthe original moon crust. From that samarium - neodymium - isotope systematics of several moon Anorthositen could be determined a crystallization age by 4,456 ± 0.04 billion years for these rocks, what as education formation of the first crust and as beginning of the crystallization of the original magma oceanone interprets.

In the high countries there are several mountains, which reach heights of approximately 10 kilometers. They resulted possibly from the fact that the moon shrank due to the cooling and thereby Faltengebirge bulged. After another explanation it could the remnants of Kraterwällen concern. They were designated after terrestrial mountains, for example alps, Apenninen, Caucasus and Karpaten. (See also: List of the mountains and mountains of the moon)


Krater Theophilus (Apollo 16, NASA)
Hadley groove(Apollo 15, NASA)

the Krater resulted majority from Asteroiden - impacts (Impaktkrater) before approximately 3 to 4.5 billion years in the early period of the moon. The nomenclature of Riccioli following, they are preferably designated after astronomers, philosophers and other scholars.Their sizes reach from 2.240 km diameters, like in the case of the South Pole Aitken basin, up to Mikrokratern, which become visible under the microscope only. With terrestrial telescopes one knows alone on the front more than 40,000 Krater with sizes ofmore than 100 meters differentiate, on the back give it however a multiple more. (See also: List of the Krater of the moon)

volcanic Krater very rarely, isolated Gasaustritte might be but become registered.


are moon grooves on the lunar surfacealso groove structures (Rima), upon whose origin before the Apolloprogramm for a long time one speculated. One differentiates between

Since the investigations of the Hadley groove by Apollo 15 one assumes it itself with the mäanderförmigen groovesaround lava channels acts, which were considered partially „“. The covers collapsed however in the course of the moon development and to Regolith grind. The developing history of the other groove forms developed clearly more uncertainly, it could however than tears in the cooling off lavaits.

Apart from structures the called Rima exist still narrow, deepened structures, which reach a length to over 400 km. They resemble the elongated grooves (Rimae) and as furrows or tears (Rupes) are designated. These furrows are considered as proof forworking tension forces within the moon crust. (See also: List of the groove structures of the moon)

back of the moon

over the back of the moon was not before the first space missions anything well-known, since it is not visible by the earth, only Lunik 3 supplied the first pictures. It differs in several aspects from the front. It consists nearly only of high countries, has however clearly more Krater, under others the large South Pole Aitken basin, 13 km of deep Krater at 2.240 kmDiameter. Investigations of the Clementine - mission and lunar the Prospector put the assumption close that a very large impact body break through the moon crust here and possibly opened mantle rocks. The moon crust is at the moon back at 150 km opposite 70 km onthe front also about twice as thickly. There is still no explanation for these fundamental differences between front and back of the moon.

The often used expression „darkens side of the moon “(Dark simmers OF the Moon) for the backthe moon is wrong in the actual sense of word, since the back in the course of the moon rotation is very probably illuminated by the sun.


the moon is an extremely dry body. In the Apollo samples water comes, in contrast z. B. to unite chondritischen meteorites, not even in form of hydratisierter minerals forwards. One estimates that the entire quantity of water of the moon corresponds only about to the quantity of water of the Zurich lake. It is the more amazing that the neighbour object, the earth, the water-richest body of the internal solar systemis.

The lunar Prospector probe found referring to water ice in the Kratern of the polar regions of the moon; this water could come out comet crashes. Since the polar Krater due to the small inclination of the moon axle against the ecliptic never directly the sun illuminatesit becomes it could be that still in the Regolith bound water ice is present there. The attempt to receive by the purposeful crash of the Prospectors in one this Polarkrater clear proofs failed however. It gives to today no proofs free of doubts.


The moon does not have an atmosphere in the actual sense, but only an exosphere. It consists too same parts of helium, neon, hydrogen as well as argon and has its origin in caught particles of the solar wind. A very small partresults also from degassings from the moon inside, whereby in particular 40 acre, which results from decay of 40 K in the moon inside, is of importance. Interestingly enough a part this 40 acre becomes however by the magnetic field along-transported in the solar windthe lunar surface back-floated and to the highest dust particle layer transferred. There 40 K in former times was more frequent and thus more 40 acre expenditure branch, can by measurement 40 acre 36 of acre relationship by moon material be determined, at which time it in the highestLayer of the Mondregoliths lay. There is an equilibrium between the caught atoms and the loss by temperature-dependent escaping.

Surface temperature

you amounts to on the page turned away from the sun -171 and on the sun side +138 degrees Celsius.

Mass of the moon

thoseDetermination of the moon mass does not represent a simple problem, since it does not result directly from the gravitation law.

A body of the mass circles <math> m< /math> a gravitation center of the mass <math> M< /math> in the distance <math> r< /math> the two centers of mass, then applies by equating the termsfor the centripetal and the gravitation strength

< math> m \ omega^2 r = \ frac {GMm} {r^2}< /math>.

The mass of the circling body stands out in this equation and it remains only the mass circled body remaining. Therefore only the mass leaves itself with this equationa planet determine, if this has a moon, which moves approach in a circular path around the planet; this applies likewise to stars, whose mass can be determined over the planets circling her.

Earth and moon place a two-body system, both partners circle their common emphasis< math> S< /math>. With the two-body system from earth and sun this emphasis coincides practically with the sun center, since the sun is very many more massive than the earth. With earth and moon is the mass difference howevernot so largely, therefore their common emphasis does not lie in the center of the earth, but removes clearly from it (however still under the surface). We designate now <math> r_1< /math> as the distance of the earth center to the emphasis <math> S< /math> and <math> r_2< /math> as the distancethe moon center of the same. There earth and moon itself both over <math> S< /math> turn, apply to both heavenly bodies the same angular speed <math> \ omega< /math>. Thus earth and moon are subject to the centripetal force in each case

<math> M \ omega^2 r_1< /math> and/or <math> m \ omega^2 r_2< /math>.

The gravitation strength working between both heavenly bodiesGMm results} { (

<r_1+r_2>) ^2} /math with the gravitation law too math \ frac< {>

By equating the terms for centripetal and gravitation strength we receive from this the equations

< math> \ to omega^2 r_1 = \ frac {GM} {(r_1+r_2) ^2}< /math>


<math> \ omega^2 r_2 = \ frac {GM} {(r_1+r_2) ^2}< /math>.

If we set these relations to each other into the relationship, then the calculation shows

<math> \ frac {r_1} {r_2} = \ frac {\ omega^2 r_1} {\ omega^2 r_2} = \ frac {\ frac {GM} {(r_1+r_2) ^2}} {\ frac {GM} {(r_1+r_2) ^2}} = \ frac {m} {M}< /math>

that the mass ratio of earth and moon straight the relationship of <math> r_1< /math> too <math> r_2< /math> corresponds. Thus it concerns, like only largely <math> r_1< /math> and <math> r_2< /math> is - thus where itself thatEmphasis of the system finds.

Without the moon and its force of gravity the earth would go through an elliptical course around the sun. However the emphasis of the system earth, moon on an elliptical course actually moves. The rotation around the common emphasisproduced so easy ripples in the Earth's orbit, which causes a small shift position of the sun seen by the earth from. Out of astronomers measured data of this shift math <r_1> /math< became> to approximately 4,700 km computes, thus 1,671 km underthe earth's surface; the radius of the earth amounts to 6,371 km. Since the moon does not describe an exact circular path around the earth, we compute <math> r_2< /math> over the middle course radius, less <math> r_1< /math>. It applies thus <math> for r_2< /math> = 384,405 km − 4,700 km = 379.705km.

Thus r_1 results} {

<r_2>} \ approx \ frac {1} {80 {,} 788} /math for the mass ratio math \ frac< {> ,

with which the moon about 81 times than the earth is easier. By using the earth mass <math> M \ approx 5 {,} 98 \ 10^ cdot {24} \ mathrm {kg}< /math> the mass of the moon results too

< math> m \ approx \ frac {M} {80 {,} 788} \ approx 7 {,} 4021 \ cdot 10^ {22}\ mathrm {kg}< /math>.


of influences of the moon on earth

correct size and distance relationship between earth and moon

the moon causes tidal effects by its gravitation on earth. Ebb-tide and tide in the seas and in the Earth's mantle brake the earth rotation and extendthus at present the days around approximately 20 microseconds per year. The Rotationsenergie of the earth is converted thereby into warmth and the angular momentum is transferred to the moon, which departs thereby around approximately 4 centimeters per year from the earth.This effect assumed for a long time is secured for approximately 1995 by laser range findings. Thereby the earth of a far (and are enough) daily the moon is caused the same side to always turn (see. Bound rotation). The moon becomes then about twice as farfar away from the earth its like today.

The moon stabilizes the axis of rotation of the earth, whose situation without this influence could not have remained over many 100 million years constantly by its portion of the overall system of the moon system also. Would be the Erdachsenot during these long periods stably remained, this serious consequences for the evolution and the life on earth would have had.

An influence of the moon on humans and other organisms on earth is still disputed. However becomes inthe land and forestry since age ago made certain that certain work in nature is settled at the correct time. In more recent time for it moon calendars are used. As strictly scientific fact secured the influence of the moon is considered as navigation aid tosome kinds of migratory birds and night-active insects.

Moon rainbow

also at night can result from meeting moon light and rain drop a moon rainbow so mentioned, which functions similarly to the physical principle of the rainbow of the sun.

Moon yard and - halo

moon yard

as moon yardcolored rings are designated around the moon, which are caused by the diffraction of the light at the water droplets of the clouds. Is the outermost ring of reddish color and has an expansion of approximately two degrees, in rare cases alsoup to ten degrees.

Colloquially the term of the moon yard is used also for a halo around the moon. But ice crystals are responsible in air layers, those from thin elevator fog or vapor developed and the light falling on earth ina very weak angle divert and thus a kind bright ring effect for the viewer cause.

Moon deception

as moon deception one designates the effect that the moon in horizon proximity looks larger than in the zenith. This is not a consequence of the refraction of light onthe air layers, but an optical deception, which is examined and explained by the perception psychology.

Ownership structures

the space contract forbids states raising a property right on space bodies like the moon. The contract applies only to states, but 1979 sketched andat the 11. July 1984 into force stepped Agreement Governing the Activities OF States on the Moon and OTHER Celestial Bodies [1] of the United Nations (article 11, paragraph 2 and 3) excludes such requirements clearly.

The American Dennis M. Hopenevertheless 1980 announced requirements for possession on the moon at the office for property of San Francisco its. Since nobody raised in the period suspended after American right from eight years objection, stated Hope, which drives properties out over its lunar Embassy created for it legallyto be able. Due to the Outer however no states of requirements can announce space Treaty, therefore also an expansion of domestic right is not permitted in opinion of all organizations (United Nations, international one astronomical union). The sales of real estate could even as fraudare rated, gives however still no judicial clarifying of this question.

The German Martin Jürgens from Westerkappeln in Westphalia lays likewise claim on the moon. According to a deed of donation of 15. July 1756, issued and signs Friedrich that from kingLarge ones of Prussia, were transferred the rights at the moon to the family Jürgens as thanks for performed services („Jetzo was to belong to it the moon “). In this document it was specified that the heavenly body to the youngest son are further-left in each caseis. The family Jürgens has in such a way the oldest confirmed by a document vested titles at the moon. However the question, who lent Friedrich the large one the right, remains the moon too „gives away “.

Possible koorbitale objects

in the Librationspunkten L4 and L5 is ittwo dust clouds, which give Kordylewski clouds.

History of the moon observation

it lies in the nature of humans to make itself over its environment thought. The moon with its even with the naked eye recognizable details is after the sun with distancebrightest object of the sky; at the same time one can observe its singular brightness - and phase changes between full moon and Neumond very well.

With the invention of the telescope its intensive research began around 1650 - with high points by Hieronymus Schröters Selenotopografie 1791,the long-focus photography starting from 1890 and space travel into the 1970ern.

Mythologi beginnings

Himmelsscheibe von Nebra
of sky disk of Nebra

the oldest well-known representation of the moon is a 5,000 years old moon map from the Irish Knowth. As the further historically meaning illustration inEurope is to be called the sky disk from Nebra to.

The stone Monument Stonehenge possibly served as observatory and was in such a way built that thereby also course characteristics of the moon were predictable or assignable.

In all archaeologically examined cultures there is referring to thosegreat ritual importance of the moon for humans at that time. The moon represented usually a central divinity , as a female goddess, for example with the Thrakern Bendis, with the Egyptians Isis, with the Greeks Selene, Artemis and Hekateas well as with the Romans Luna and Diana, or as male God as for example with the Sumerern Nanna, in Egypt Thot, in Japan Tsukiyomi, with the Aztecs Tecciztecatl and with the Teutons Mani. Nearly always becameSun and moon thereby as opposite sexually meant, even if the allocation varied.

A frequently occurring thought is the picture of the three faces of the moon goddess: with increasing moon the seductive virgin of full Sexualität, with full moon the fruitful nut/mother andwith removing moon the old woman or the witch with Kraft to healing, for example with the Greeks with kind bad, Selene and Hekate as well as with the Celts Blodeuwedd, Morrigan and Ceridwen.

The moon has into thoseModern times inside its fascination lost and are not to today article of novels and fictions, of Jules Vernes „journey to the moon “over Paul Linckes „Mrs. Luna “up to „the modern “dream of a settling of the moon.


beside thatour ancestors used mythologischen admiration already very early the regular and easily visible rhythm of the moon for the description of time intervals and as basis of a calendar, this very day are based the Islamic calendar on the moon year with 354 days (12synodische months). With the transition to the agriculture the meaning of the yearly process for sowing and harvest became more important. In order to consider this, first as required, later using being certain formulas like for example the metonischen cycle switching months were inserted, those the moon yearwith the sun year synchronized. On this lunisolaren pattern for example the old-Greek and the Jewish calendar are based. From the old advanced cultures only the Egyptians had a pure sun year with 12 months à 30 days as well as 5 intercalary days, i.e.without strict purchase to the synodischen month of 29,5 days, probably because for the Egyptian culture the exact forecast of the Nile inundations and thus the process of the sun yearly were survive necessary.

Development of the moon research

first, even if only sketchy representation of the visibleStructures of the moon comes from Galileo Galilei (1609), the first useful come from Johannes Hevelius, which applies with its work Selenographia (1647) as a founder of the Selenographie. In the nomenclature of the moon structures the system sat downof Giovanni Riccioli through, which called the darker regions seas (Mare, Plural Maria) and the Krater in its maps of 1651 after philosophers and astronomers. Generally recognition this system is however only since that 19. Century.

Thousands of detail designs of mountains, Kratern and barrier levels were made by Johann Hieronymus Schröter (1778-1813), also many moon valleys and grooves discovered. The first moon Atlas publication William Beer and Johann Heinrich Mädler 1837, him followed soon a long rowphotographic Atlases. The quality of the maps was improved clearly into the 1960ern, as for the preparation of the Apollo project a mapping by lunar the orbiters - probes from a moon orbit took place. The today most exact maps originate from the 1990ern by those Clementine - and lunar Prospector - missions.

The first photo of the back of the moon, taken up of Lunik 3

the Höhenbestimmung of Kratern, mountains and levels was very problematic with telescope observations and took place usually via analysis from Schattenlängen, for which Josef Hopmann special methods developed.Only by the probe mapping one knows reliable values: the Krater, with diameters up to 300 kilometers, work steeply, are however only bent few degrees, the highest collections however reach a height of up to 10 kilometers over the middleLevel.

An important progress in the investigation of the moon was obtained by the satellite missions. The Soviet probe Lunik 1 approximated for the first time the moon 65,000 km, Lunik 2 finally met it and Lunik 3 supplied the first pictures of the moon back. The US-American Apollo and the Soviet Luna program returned with nine missions between 1969 and 1976 to altogether 382 kilograms moon rock from the moon front to the earth. The following table gives an overview of the missions, which led back rock samples to the earth.

Date mission quantity of landing place
20. July 1969 Apollo 11 21.6 kg of Mare Tranquillitatis
19. November 1969 Apollo 12 34.3 kg of Oceanus Procellarum
20. September 1970 Luna 16 ,100 g Mare Fecunditatis
31. January 1971 Apollo 14 42.6 kg of Fra MauroHigh country
30. July 1971 Apollo 15 77.3 kg of Hadley Apenninen (Mare and high country)
21. February 1972 Luna 20 30 g Apollonius high country
21. April 1972 Apollo 16 95.7 kg of Descartes
11. December 1972 Apollo 17 110.5 kg of Taurus Littrow (Mare and high country)
18. August 1976 Luna 24 ,170 g Mare Crisium

1979 was discovered the first moon meteorite in the Antarctic, whose origin was recognized by the moon however only some years later. Meanwhile one knows still more than two dozen further. These forma complementary source of information to the rocks, which were brought by the moon missions to the earth: While one knows the exact origin with the Apollo and Lunaproben, the Meteorite, despite the unawareness of its exact place of origin on the moon, might more representatively for thoseLunar surface its, there some from statistic reasons also from the back of the moon to originate should.

Humans on the moon

Edwin Aldrin/Apollo 11
map of the landing places of the manned and unmanned missions

in the context of the cold war undertook the USA and the USSR into the 1960ern an approach to manned moon-landings, which were realized however only by the USA. To 21. July 1969 put its foot on with Neil Armstrong first of 12 astronauts in the context of the Apollo projectthe moon, because of the high costs the program was stopped after six successful missions 1972. During outgoing 20. Century one speculated to that again and again upon a return to the moon and the mechanism of a constant moon basis, but only by announcementsUS president George W. Bush and NASA at the beginning of 2004 appear concrete plans. Therefore the USA plan to send to again four astronauts in the year 2018 on the moon.

Chronological list of the 12 men, who entered the moon.

  1. NeilA. Armstrong
  2. Edwin E. „Buzz “Aldrin
  3. Charles P. Conrad
  4. Alan L. Bean
  5. Alan B. Shepard
  6. Edgar D. Mitchell
  7. David R. Scott
  8. James B. Irwin
  9. John W. Young
  10. Charles M. Duke
  11. Eugene A. Cernan
  12. Harrison H. Schmitt

as last humansEugene A. left. Cernan the moon.


  • faith it really, which moon is not since, except if someone looks? - Albert Einstein to representatives of the quantum theory.


  • Peter Janle: The picture of the moon from the antiquity to the beginning of the Weltraumfahrt. Stars and space 38 (8), S. 640 - 647 (1999), ISSN 0039-1263

see also

Wikiquote: Moon - quotations

Web on the left of

Wiktionary: Moon - word origin, synonyms and translations
Commons: Moon- Pictures, videos and/or audio files


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