Outer core - wikipedia Outer core For the cores of other planetary bodies, see Planetary core. For a broader coverage related to this topic, see Earth core. The internal structure of Earth The outer core of the Earth is a fluid layer about 2,400 km ( 1,500 mi ) thick and composed of mostly iron and nickel that lies above Earth 's solid inner core and below its mantle. Its outer boundary lies 2,890 km ( 1,800 mi ) beneath Earth 's surface. The transition between the inner core and outer core is located approximately 5,150 km ( 3,200 mi ) beneath the Earth 's surface. Unlike the inner core, the outer core is liquid. The inner core is also referred to as the solid core. Contents 1 Properties 2 See also 3 References 4 External links Properties Seismic inversions of body waves and normal modes constrain the radius of the outer core to be 3483 km with an uncertainty of 5 km, while that of the inner core is 1220 ± 10 km. Estimates for the temperature of the outer core are about 3,000 -- 4,500 K ( 2,730 -- 4,230 ° C ; 4,940 -- 7,640 ° F ) in its outer regions and 4,000 -- 8,000 K ( 3,730 -- 7,730 ° C ; 6,740 -- 13,940 ° F ) near the inner core. Evidence for a fluid outer core includes from seismology which shows that seismic shear - waves are not transmitted through the outer core Because of its high temperature, modeling work has shown that the outer core is a low viscosity fluid that convects turbulently. Eddy currents in the nickel iron fluid of the outer core are believed to influence the Earth 's magnetic field. The average magnetic field strength in the Earth 's outer core was measured to be 2.5 millitesla, 50 times stronger than the magnetic field at the surface. The outer core is not under enough pressure to be solid, so it is liquid even though it has a composition similar to the inner core. Sulfur and oxygen could be present in the outer core. As heat is transferred outward toward the mantle, the net trend is for the inner boundary of the liquid region to freeze, causing the solid inner core to grow. This growth rate is estimated to be 1 mm per year. See also Structure of the Earth References Jump up ^ https://www.nationalgeographic.com/science/earth/surface-of-the-earth/earths-interior/ Jump up ^ Beno Gutenberg ( 4 June 2016 ). Physics of the Earth 's Interior. Elsevier. pp. 115 --. ISBN 978 - 1 - 4832 - 8212 - 1. Jump up ^ Ahrens, Thomas J., ed. ( 1995 ). Global earth physics a handbook of physical constants ( 3rd ed. ). Washington, DC : American Geophysical Union. ISBN 9780875908519. ^ Jump up to : De Wijs, Gilles A. ; Kresse, Georg ; Vočadlo, Lidunka ; Dobson, David ; Alfè, Dario ; Gillan, Michael J. ; Price, Geoffrey D. ( 1998 ). `` The viscosity of liquid iron at the physical conditions of the Earth 's core '' ( PDF ). Nature. 392 ( 6678 ) : 805. Bibcode : 1998Natur. 392... 805D. doi : 10.1038 / 33905. Jump up ^ Jeffreys, Harold ( 1926 - 06 - 01 ). `` The Rigidity of the Earth 's Central Core ''. Monthly Notices of the Royal Astronomical Society. 1 : 371 -- 383. Bibcode : 1926GeoJ... 1... 371J. doi : 10.1111 / j. 1365 - 246X. 1926. tb05385. x. ISSN 1365 - 246X. Jump up ^ First Measurement Of Magnetic Field Inside Earth 's Core. Science20.com. Retrieved on 2012 - 01 - 27. Jump up ^ Buffett, Bruce A. ( 2010 ). `` Tidal dissipation and the strength of the Earth 's internal magnetic field ''. Nature. 468 ( 7326 ) : 952 -- 4. Bibcode : 2010Natur. 468... 952B. doi : 10.1038 / nature09643. PMID 21164483. Jump up ^ Gubbins, David ; Sreenivasan, Binod ; Mound, Jon ; Rost, Sebastian ( May 19, 2011 ). `` Melting of the Earth 's inner core ''. Nature. 473 ( 7347 ) : 361 -- 363. Bibcode : 2011Natur. 473... 361G. doi : 10.1038 / nature10068. PMID 21593868. Jump up ^ Waszek, Lauren ; Irving, Jessica ; Deuss, Arwen ( 2011 ). `` Reconciling the hemispherical structure of Earth 's inner core with its super-rotation ''. Nature Geoscience. 4 : 264 -- 267. Bibcode : 2011NatGe... 4... 264W. doi : 10.1038 / ngeo1083. External links The Wikibook Historical Geology has a page on the topic of : Structure of the Earth Planet Earth from universetoday.com Earth - related topics History Age of the Earth Evolutionary history of life Faint young Sun paradox Formation and evolution of the Solar System Future of Earth Geologic time scale Geological history of Earth History of Earth Timeline of evolution Geography Geology Clairaut 's theorem Continents Earthquake Equatorial bulge Extremes on Earth Geology of solar terrestrial planets Geophysics Plate tectonics Structure of the Earth Time zones Ecology Earth Day Global warming Human impact on the environment Imaging Apple Maps Baidu Maps Bhuvan Bing Maps Global Map Google Earth Google Maps MapmyIndia NASA World Wind Here OpenStreetMap Wikimapia Remote sensing Yahoo ! Maps Yandex Maps Arts Culture Society Earth in culture Earth in science fiction Etymology of the word `` Earth '' History of the world International law Landscape painting List of countries World economy Other topics Biosphere Earth 's orbit Earth trojan The ecliptic Flag of Earth Gravity Magnetic field The Moon Claimed moons of Earth 2006 RH120 Kordylewski cloud Solar System Earth 's location in the Universe Theia Earth sciences portal Solar System portal Structure of the Earth Shells Crust Lithosphere Mesosphere Mantle Asthenosphere Lithospheric mantle Subcontinental lithospheric mantle Oceanic lithospheric mantle Outer core Inner core Discontinuities Conrad ( continental crust ) Mohorovičić ( crust -- mantle ) Lehmann ( upper mantle ) Gutenberg ( mantle -- core ) Lehmann ( core ) Arguments Plate tectonics Retrieved from `` https://en.wikipedia.org/w/index.php?title=Outer_core&oldid=840103243 '' Categories : Structure of the Earth Geomagnetism Talk Contents About Wikipedia Català Deutsch Eesti Español فارسی Français Galego 한국어 हिन्दी Bahasa Indonesia Italiano Magyar Bahasa Melayu Nederlands 日本 語 Norsk Norsk nynorsk پنجابی Português Русский Српски / srpski தமிழ் Türkçe Українська Tiếng Việt 中文 18 more Edit links This page was last edited on 7 May 2018, at 19 : 00. Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. About Wikipedia

Question: what is the outer core of earth made up of
Answer: iron