Editing Internal structure of Earth (section)

=== Mantle ===
{{Main|Earth's mantle}}
[[File:Subduction-en.svg|left|thumb|300x300px|Earth's crust and mantle, [[Mohorovičić discontinuity]] between bottom of crust and solid uppermost mantle]]
Earth's mantle extends to a depth of {{convert|2,890|km|abbr=on}}, making it the planet's thickest layer.<ref>{{cite news |url=https://www.forbes.com/sites/trevornace/2016/01/16/layers-of-the-earth-lies-beneath-earths-crust/ |title=Layers Of The Earth: What Lies Beneath Earth's Crust |first=Trevor |last=Nace |date=16 January 2016 |access-date=28 June 2019 |magazine=[[Forbes]] |archive-date=5 March 2020 |archive-url=https://web.archive.org/web/20200305220618/https://www.forbes.com/sites/trevornace/2016/01/16/layers-of-the-earth-lies-beneath-earths-crust/ |url-status=live }}</ref>
[This is 45% of the 
{{convert|6,371|km|abbr=on}} radius, and 83.7% of the volume -  0.6% of the volume is the crust].
The mantle is divided into [[upper mantle|upper]] and [[lower mantle]]<ref>{{cite journal |url=https://education.nationalgeographic.org/resource/mantle/ |title=Mantle |first=Jeannie |last=Evers |date=11 August 2015 |access-date=28 June 2019 |journal=[[National Geographic]] |publisher=[[National Geographic Society]] |archive-date=12 May 2016 |archive-url=https://web.archive.org/web/20160512171916/https://www.nationalgeographic.org/encyclopedia/mantle/ |url-status=live }}</ref> separated by a [[Transition zone (Earth)|transition zone]].<ref>{{cite journal |journal=[[Nat Commun]] |volume=9 |date=28 March 2018 |issue=9 |page=1266 |doi=10.1038/s41467-018-03654-6 |pmc=5872023 |pmid=29593266 |title=Compositional heterogeneity near the base of the mantle transition zone beneath Hawaii |first1=Chunquan |last1=Yu |first2=Elizabeth A. |last2=Day |first3=Maarten V. |last3=de Hoop |first4=Michel |last4=Campillo |first5=Saskia |last5=Goes |first6=Rachel A. |last6=Blythe |first7=Robert D. |last7=van der Hilst |bibcode=2018NatCo...9.1266Y }}</ref> The lowest part of the mantle next to the [[core-mantle boundary]] is known as the D″ (D-double-prime) layer.<ref name="DDoublePron">{{cite news |url=https://www.science.org/content/article/d-layer-demystified |title=''D'' Layer Demystified |publisher=[[American Association for the Advancement of Science]] |magazine=[[Science News]] |date=24 March 2004 |access-date=5 November 2016 |last=Krieger |first=Kim |archive-date=10 July 2022 |archive-url=https://web.archive.org/web/20220710170436/https://www.science.org/content/article/d-layer-demystified |url-status=live }}</ref> The [[pressure]] at the bottom of the mantle is ≈140 G[[pascal (unit)|Pa]] (1.4 M[[Atmosphere (unit)|atm]]).<ref>{{cite journal |url=https://www.unr.edu/Documents/science/mackay/coring%20the%20earth.pdf |title=Coring the Earth |first=Rachel |last=Dolbier |journal=[[W. M. Keck Earth Science and Mineral Engineering Museum]] |publisher=[[University of Nevada, Reno]] |pages=5 |access-date=28 June 2019 |archive-date=7 September 2015 |archive-url=https://web.archive.org/web/20150907215534/http://www.unr.edu/Documents/science/mackay/coring%20the%20earth.pdf |url-status=dead }}</ref> The mantle is composed of [[silicate]] rocks richer in iron and magnesium than the overlying crust.<ref>{{cite news |url=https://www.universetoday.com/40229/what-is-the-earths-mantle-made-of/ |title=What is the Earth's Mantle Made Of? |date=26 March 2016 |access-date=28 June 2019 |first=Fraser |last=Cain |work=[[Universe Today]] |archive-date=6 November 2010 |archive-url=https://web.archive.org/web/20101106115153/https://www.universetoday.com/40229/what-is-the-earths-mantle-made-of/ |url-status=live }}</ref> Although solid, the mantle's extremely hot silicate material can [[Ductility|flow]] over very long timescales.<ref>{{cite news |url=https://sciencing.com/different-properties-asthenosphere-lithosphere-8447830.html |title=The Different Properties of the Asthenosphere & the Lithosphere |date=22 October 2018 |access-date=28 June 2019 |first=Ethan |last=Shaw |work=Sciencing |publisher=[[Leaf Group]] Media |archive-date=30 July 2020 |archive-url=https://web.archive.org/web/20200730055603/https://sciencing.com/different-properties-asthenosphere-lithosphere-8447830.html |url-status=live }}</ref> [[Convection]] of the mantle propels the [[plate tectonics|motion of the tectonic plates]] in the crust. The [[Earth's internal heat budget|source of heat]] that drives this motion is the decay of [[radioactive isotopes]] in Earth's crust and mantle combined with the initial heat from the planet's formation<ref>{{cite journal|last=Preuss|first=Paul|date=July 17, 2011|title=What Keeps the Earth Cooking?|url=http://newscenter.lbl.gov/2011/07/17/kamland-geoneutrinos/|journal=[[Lawrence Berkeley National Laboratory]]|publisher=[[University of California, Berkeley]]|access-date=28 June 2019|archive-date=21 January 2022|archive-url=https://web.archive.org/web/20220121083440/https://newscenter.lbl.gov/2011/07/17/kamland-geoneutrinos/|url-status=live }}</ref> (from the [[potential energy]] released by collapsing a large amount of matter into a [[gravity well]], and the [[kinetic energy]] of accreted matter).

Due to increasing pressure deeper in the mantle, the lower part flows less easily, though chemical changes within the mantle may also be important. The viscosity of the mantle ranges between 10<sup>21</sup> and 10<sup>24</sup> [[pascal second|pascal-second]], increasing with depth.<ref>{{cite journal |first1=Uwe |last1=Walzer |first2=Roland |last2=Hendel |first3=John |last3=Baumgardner |author3-link=John Baumgardner |archive-url=https://web.archive.org/web/20060826020002/http://www.chemie.uni-jena.de/geowiss/geodyn/poster2.html |title=Mantle Viscosity and the Thickness of the Convective Downwellings |url=http://www.chemie.uni-jena.de/geowiss/geodyn/poster2.html |archive-date=26 August 2006 |access-date=28 June 2019 |journal=[[Los Alamos National Laboratory]] |publisher=[[Universität Heidelberg]]}}</ref> In comparison, the viscosity of water at {{convert|300|K}} is 0.89 millipascal-second <ref>{{Cite book |url= |title=[[CRC Handbook of Chemistry and Physics]] |publisher=[[CRC Press]] |year=2017 |isbn=978-1-4987-5429-3 |editor-last=Haynes |editor-first=William M. |edition=97th |location=Boca Raton, Florida |at=Section 6 page 247 |oclc=957751024 |editor-last2=David R. |editor-first2=Lide |editor-last3=Bruno |editor-first3=Thomas J.}}</ref> and [[Pitch (resin)|pitch]] is (2.3 ± 0.5) × 10<sup>8</sup> pascal-second.<ref name="pitchdrop">{{cite web |last1=Edgeworth |first1=R. |last2=Dalton |first2=B.J. |last3=Parnell |first3=T. |title=The Pitch Drop Experiment |url=http://www.physics.uq.edu.au/physics_museum/pitchdrop.shtml |url-status=dead |archive-url=https://web.archive.org/web/20130328064508/http://www.physics.uq.edu.au/physics_museum/pitchdrop.shtml |archive-date=28 March 2013 |access-date=15 October 2007 |publisher=The University of Queensland Australia}}</ref>