Having a mean density of 3,346.4 kg/m3,[2] the Moon is a differentiated body, being composed of a geochemically distinct crust, mantle, and planetary core. This structure is believed to have resulted from the fractional crystallization of a magma ocean shortly after its formation about 4.5 billion years ago. The energy required to melt the outer portion of the Moon is commonly attributed to a giant impact event that is postulated to have formed the Earth-Moon system, and the subsequent reaccretion of material in Earth orbit. Crystallization of this magma ocean would have given rise to a mafic mantle and a plagioclase-rich crust.
Moon's internal structureOlivinebasalt collected by Apollo 15.Thermal state of the Moon at age 100 Ma.[1]
Geochemical mapping from orbit implies that the crust of the Moon is largely anorthositic in composition,[3] consistent with the magma ocean hypothesis. In terms of elements, the lunar crust is composed primarily of oxygen, silicon, magnesium, iron, calcium, and aluminium, but important minor and trace elements such as titanium, uranium, thorium, potassium, sulphur, manganese, chromium[4] and hydrogen are present as well. Based on geophysical techniques, the crust is estimated to be on average about 50 km thick.[5]
Partial melting within the mantle of the Moon gave rise to the eruption of mare basalts on the lunar surface. Analyses of these basalts indicate that the mantle is composed predominantly of the minerals olivine, orthopyroxene and clinopyroxene, and that the lunar mantle is more iron-rich than that of the Earth. Some lunar basalts contain high abundances of titanium (present in the mineral ilmenite), suggesting that the mantle is highly heterogeneous in composition. Moonquakes have been found to occur deep within the mantle of the Moon about 1,000 km below the surface. These occur with monthly periodicities and are related to tidal stresses caused by the eccentric orbit of the Moon about the Earth. A few shallow moonquakes with hypocenters located about 100 km below the surface have also been detected, but these occur more infrequently and appear to be unrelated to the lunar tides.[5]
Schematic illustration of the internal structure of the Moon
Several lines of evidence imply that the lunar core is small, with a radius of about 350 km or less.[5] The size of the lunar core is only about 20% the size of the Moon itself, in contrast to about 50% as is the case for most other terrestrial bodies. The composition of the lunar core is not well constrained, but most believe that it is composed of metallic iron alloy with a small amount of sulfur and nickel. Analyses of the Moon's time-variable rotations indicate that the core is at least partly molten.[6] Within the giant-impact formation scenario, the core formation of Moon could have occurred within the initial 100–1000 years from the commencement of its accretion from its moonlets. [7]
In 2010, a reanalysis of the old Apollo seismic data on the deep moonquakes using modern processing methods confirmed that the Moon has an iron rich core with a radius of 330 ± 20 km. The same reanalysis established that the solid inner core made of pure iron has a radius of 240 ± 10 km. The core is surrounded by the partially (10 to 30%) melted layer of the lower mantle with a radius of 480 ± 20 km (thickness ~150 km). These results imply that 40% of the core by volume has solidified. The density of the liquid outer core is about 5 g/cm3 and it could contain as much as 6% sulfur by weight. The temperature in the core is probably about 1600–1700 K (1330–1430 °C).[8]
Ancient rift valleys – closeup (artist's concept).
In 2019, a reanalysis of nearly 50 years of data collected from the Lunar Laser Ranging experiment with lunar gravity field data from the GRAIL mission, shows that for a relaxed lunar fluid core with non-hydrostatic lithospheres, the core flattening is determined as (2.2±0.6)×10−4 with the radii of its core-mantle boundary as 381±12 km.[9]
^Maurice, M.; Tosi, N.; Schwinger, S.; Breuer, D.; Kleine, T. (1 July 2020). "A long-lived magma ocean on a young Moon". Science Advances. 6 (28): eaba8949. Bibcode:2020SciA....6.8949M. doi:10.1126/sciadv.aba8949. ISSN 2375-2548. PMC7351470. PMID 32695879. Text and images are available under a Creative Commons Attribution 4.0 International License.
^Making it the second densest satellite in the Solar System after Io
^P. Lucey and 12 coauthors, P. (2006). "Understanding the lunar surface and space-Moon interactions". Reviews in Mineralogy and Geochemistry. 60 (1): 83–219. Bibcode:2006RvMG...60...83L. doi:10.2138/rmg.2006.60.2.{{cite journal}}: CS1 maint: numeric names: authors list (link)
^"What Chandrayaan 3 has found on moon so far: Oxygen, sulphur, iron, silicon". Hindustan Times. 2023-08-30. Retrieved 2023-11-15.
^ abcMark Wieczorek and 15 coauthors, M. A. (2006). (PDF). Reviews in Mineralogy and Geochemistry. 60 (1): 221–364. Bibcode:2006RvMG...60..221W. doi:10.2138/rmg.2006.60.3. Archived from the original (PDF) on 2014-12-21.{{cite journal}}: CS1 maint: numeric names: authors list (link)
^J. G. Williams; S. G. Turyshev; D. H. Boggs; J. T. Ratcliff (2006). "Lunar laser ranging science: Gravitational physics and lunar interior and geodesy". Advances in Space Research. 37 (1): 67–71. arXiv:gr-qc/0412049. Bibcode:2006AdSpR..37...67W. doi:10.1016/j.asr.2005.05.013. S2CID 14801321.
^S. Sahijpal; V. Goyal (2018). "Thermal evolution of the early Moon". Meteoritics and Planetary Science Journal. 53 (10): 2193–2211. arXiv:2001.07123. Bibcode:2018M&PS...53.2193S. doi:10.1111/maps.13119. S2CID 134291699.
^Weber, R. C.; Lin, P.-Y.; Garnero, E. J.; Williams, Q.; Lognonne, P. (2011). "Seismic Detection of the Lunar Core". Science. 331 (6015): 309–312. Bibcode:2011Sci...331..309W. doi:10.1126/science.1199375. PMID 21212323. S2CID 206530647.
^Viswanathan, V.; Rambaux, N.; Fienga, A.; Laskar, J.; Gastineau, M. (9 July 2019). "Observational Constraint on the Radius and Oblateness of the Lunar Core-Mantle Boundary". Geophysical Research Letters. 46 (13): 7295–7303. arXiv:1903.07205. Bibcode:2019GeoRL..46.7295V. doi:10.1029/2019GL082677. S2CID 119508748.
External linksedit
Moon articles in Planetary Science Research Discoveries, including articles about internal structure of the Moon
January 01, 1970
internal, structure, moon, also, geology, moon, having, mean, density, moon, differentiated, body, being, composed, geochemically, distinct, crust, mantle, planetary, core, this, structure, believed, have, resulted, from, fractional, crystallization, magma, oc. See also Geology of the Moon Having a mean density of 3 346 4 kg m3 2 the Moon is a differentiated body being composed of a geochemically distinct crust mantle and planetary core This structure is believed to have resulted from the fractional crystallization of a magma ocean shortly after its formation about 4 5 billion years ago The energy required to melt the outer portion of the Moon is commonly attributed to a giant impact event that is postulated to have formed the Earth Moon system and the subsequent reaccretion of material in Earth orbit Crystallization of this magma ocean would have given rise to a mafic mantle and a plagioclase rich crust Moon s internal structure Olivine basalt collected by Apollo 15 Thermal state of the Moon at age 100 Ma 1 Geochemical mapping from orbit implies that the crust of the Moon is largely anorthositic in composition 3 consistent with the magma ocean hypothesis In terms of elements the lunar crust is composed primarily of oxygen silicon magnesium iron calcium and aluminium but important minor and trace elements such as titanium uranium thorium potassium sulphur manganese chromium 4 and hydrogen are present as well Based on geophysical techniques the crust is estimated to be on average about 50 km thick 5 Partial melting within the mantle of the Moon gave rise to the eruption of mare basalts on the lunar surface Analyses of these basalts indicate that the mantle is composed predominantly of the minerals olivine orthopyroxene and clinopyroxene and that the lunar mantle is more iron rich than that of the Earth Some lunar basalts contain high abundances of titanium present in the mineral ilmenite suggesting that the mantle is highly heterogeneous in composition Moonquakes have been found to occur deep within the mantle of the Moon about 1 000 km below the surface These occur with monthly periodicities and are related to tidal stresses caused by the eccentric orbit of the Moon about the Earth A few shallow moonquakes with hypocenters located about 100 km below the surface have also been detected but these occur more infrequently and appear to be unrelated to the lunar tides 5 Contents 1 Core 2 See also 3 References 4 External linksCore edit nbsp Schematic illustration of the internal structure of the Moon Several lines of evidence imply that the lunar core is small with a radius of about 350 km or less 5 The size of the lunar core is only about 20 the size of the Moon itself in contrast to about 50 as is the case for most other terrestrial bodies The composition of the lunar core is not well constrained but most believe that it is composed of metallic iron alloy with a small amount of sulfur and nickel Analyses of the Moon s time variable rotations indicate that the core is at least partly molten 6 Within the giant impact formation scenario the core formation of Moon could have occurred within the initial 100 1000 years from the commencement of its accretion from its moonlets 7 In 2010 a reanalysis of the old Apollo seismic data on the deep moonquakes using modern processing methods confirmed that the Moon has an iron rich core with a radius of 330 20 km The same reanalysis established that the solid inner core made of pure iron has a radius of 240 10 km The core is surrounded by the partially 10 to 30 melted layer of the lower mantle with a radius of 480 20 km thickness 150 km These results imply that 40 of the core by volume has solidified The density of the liquid outer core is about 5 g cm3 and it could contain as much as 6 sulfur by weight The temperature in the core is probably about 1600 1700 K 1330 1430 C 8 Moon Oceanus Procellarum Ocean of Storms nbsp Ancient rift valleys rectangular structure visible topography GRAIL gravity gradients October 1 2014 nbsp Ancient rift valleys context nbsp Ancient rift valleys closeup artist s concept In 2019 a reanalysis of nearly 50 years of data collected from the Lunar Laser Ranging experiment with lunar gravity field data from the GRAIL mission shows that for a relaxed lunar fluid core with non hydrostatic lithospheres the core flattening is determined as 2 2 0 6 10 4 with the radii of its core mantle boundary as 381 12 km 9 See also edit nbsp Solar System portal Lunar resources Structure of the EarthReferences edit Maurice M Tosi N Schwinger S Breuer D Kleine T 1 July 2020 A long lived magma ocean on a young Moon Science Advances 6 28 eaba8949 Bibcode 2020SciA 6 8949M doi 10 1126 sciadv aba8949 ISSN 2375 2548 PMC 7351470 PMID 32695879 nbsp Text and images are available under a Creative Commons Attribution 4 0 International License Making it the second densest satellite in the Solar System after Io P Lucey and 12 coauthors P 2006 Understanding the lunar surface and space Moon interactions Reviews in Mineralogy and Geochemistry 60 1 83 219 Bibcode 2006RvMG 60 83L doi 10 2138 rmg 2006 60 2 a href Template Cite journal html title Template Cite journal cite journal a CS1 maint numeric names authors list link What Chandrayaan 3 has found on moon so far Oxygen sulphur iron silicon Hindustan Times 2023 08 30 Retrieved 2023 11 15 a b c Mark Wieczorek and 15 coauthors M A 2006 The constitution and structure of the lunar interior PDF Reviews in Mineralogy and Geochemistry 60 1 221 364 Bibcode 2006RvMG 60 221W doi 10 2138 rmg 2006 60 3 Archived from the original PDF on 2014 12 21 a href Template Cite journal html title Template Cite journal cite journal a CS1 maint numeric names authors list link J G Williams S G Turyshev D H Boggs J T Ratcliff 2006 Lunar laser ranging science Gravitational physics and lunar interior and geodesy Advances in Space Research 37 1 67 71 arXiv gr qc 0412049 Bibcode 2006AdSpR 37 67W doi 10 1016 j asr 2005 05 013 S2CID 14801321 S Sahijpal V Goyal 2018 Thermal evolution of the early Moon Meteoritics and Planetary Science Journal 53 10 2193 2211 arXiv 2001 07123 Bibcode 2018M amp PS 53 2193S doi 10 1111 maps 13119 S2CID 134291699 Weber R C Lin P Y Garnero E J Williams Q Lognonne P 2011 Seismic Detection of the Lunar Core Science 331 6015 309 312 Bibcode 2011Sci 331 309W doi 10 1126 science 1199375 PMID 21212323 S2CID 206530647 Viswanathan V Rambaux N Fienga A Laskar J Gastineau M 9 July 2019 Observational Constraint on the Radius and Oblateness of the Lunar Core Mantle Boundary Geophysical Research Letters 46 13 7295 7303 arXiv 1903 07205 Bibcode 2019GeoRL 46 7295V doi 10 1029 2019GL082677 S2CID 119508748 External links editMoon articles in Planetary Science Research Discoveries including articles about internal structure of the Moon Retrieved from https en wikipedia org w index php title Internal structure of the Moon amp oldid 1188206984, wikipedia, wiki, book, books, library,
