Editing Earth (section)

=== Internal heat ===
{{Main|Earth's internal heat budget}}
[[File:Earth heat flow.jpg|upright=1.3|thumb|A map of [[heat flow]] from Earth's interior to the surface of Earth's crust, mostly along the [[oceanic ridge]]s]]
The major contributors to Earth's internal heat are primordial heat (heat left over from Earth's formation) and radiogenic heat (heat produced by radioactive decay).<ref name=Turcotte>{{cite book|author1=Donald L. Turcotte|author2=Gerald Schubert|title=Geodynamics|url=https://books.google.com/books?id=-nCHlVuJ4FoC&q=primordial&pg=PA286|date=25 March 2002|publisher=Cambridge University Press|isbn=978-0-521-66624-4}}</ref> The major heat-producing [[isotope]]s within Earth are [[potassium-40]], [[uranium-238]], and [[thorium-232]].<ref name=sanders20031210 /> At the center, the temperature may be up to {{convert|6000|C|F}},<ref>{{cite web |title=The Earth's Centre is 1000 Degrees Hotter than Previously Thought |url=http://www.esrf.eu/news/general/Earth-Center-Hotter |website=The European Synchrotron (ESRF) |access-date=12 April 2015 |archive-url=https://web.archive.org/web/20130628075455/http://www.esrf.eu/news/general/Earth-Center-Hotter/Earth-Centre-Hotter/ |archive-date=28 June 2013 |date=25 April 2013 |url-status=dead }}</ref> and the pressure could reach {{convert|360|GPa|e6psi|abbr=unit|lk=on}}.<ref name=ptrsl360_1795_1227 /> Because much of the heat is provided by radioactive decay, scientists postulate that early in Earth's history, before isotopes with short half-lives were depleted, Earth's heat production was much higher. At approximately {{val|3|ul=Gyr}}, twice the present-day heat would have been produced, increasing the rates of [[mantle convection]] and plate tectonics, and allowing the production of uncommon [[igneous rock]]s such as [[komatiite]]s that are rarely formed today.<ref name="T&S 137" /><ref name=epsl121_1 />

The mean heat loss from Earth is {{val|87|u=mW/m<sup>2</sup>}}, for a global heat loss of {{val|4.42|e=13|u=W}}.<ref name=jg31_3_267 /> A portion of the core's thermal energy is transported toward the crust by [[mantle plume]]s, a form of convection consisting of upwellings of higher-temperature rock. These plumes can produce [[Hotspot (geology)|hotspots]] and [[flood basalt]]s.<ref name=science246_4926_103 /> More of the heat in Earth is lost through plate tectonics, by mantle upwelling associated with [[mid-ocean ridge]]s. The final major mode of heat loss is through conduction through the lithosphere, the majority of which occurs under the oceans.<ref name="heat loss" />