Editing Internal structure of Earth (section)

==Global properties==
{{Further|Earth#Physical characteristics}}{{Expand section|date=August 2022}}
{| class="wikitable"
|+Chemical composition of the upper internal structure of [[Earth]]<ref name=":1">{{Cite book |url=http://assets.press.princeton.edu/chapters/s7559.pdf |title=The Structure of Earth and Its Constituents |publisher=Princeton University Press |pages=4}}</ref>
!Chemical element
![[Continental crust]] (%)
![[Upper mantle]] (%)
![[Pyrolite|Pyrolite model]] (%)
!Chondrite model (1) (%)
!Chondrite model (2) (%)
|-
|[[Magnesium oxide|MgO]]
|4.4
|36.6
|38.1
|26.3
|38.1
|-
|[[Aluminium oxide|Al<sub>2</sub>O<sub>3</sub>]]
|15.8
|4.6
|4.6
|2.7
|3.9
|-
|[[Silicon dioxide|SiO<sub>2</sub>]]
|59.1
|45.4
|45.1
|29.8
|43.2
|-
|[[Calcium oxide|CaO]]
|6.4
|3.7
|3.1
|2.6
|3.9
|-
|[[Iron(II) oxide|FeO]]
|6.6
|8.1
|7.9
|6.4
|9.3
|-
|Other oxides
|7.7
|1.4
|1.2
|N/A
|5.5
|-
|[[Iron|Fe]]
|N/A 
|N/A
|N/A
|25.8
|N/A
|-
|[[Nickel|Ni]]
|N/A 
|N/A
|N/A
|1.7
|N/A
|-
|[[Silicon|Si]]
|N/A
|N/A
|N/A
|3.5
|N/A
|}
Note: In chondrite model (1), the light element in the core is assumed to be Si. Chondrite model (2) is a model of chemical composition of the mantle corresponding to the model of core shown in chondrite model (1).<ref name=":1" />[[File:The Blue Marble (remastered).jpg|alt=see caption|thumb|A [[The Blue Marble|photograph of Earth]] taken by the crew of [[Apollo 17]] in 1972. A processed version became widely known as ''[[The Blue Marble]]''.<ref name="Petsko">{{cite journal |last=Petsko |first=Gregory A. |author-link=Gregory Petsko |date=28 April 2011 |title=The blue marble |journal=[[Genome Biology]] |volume=12 |issue=4 |page=112 |doi=10.1186/gb-2011-12-4-112 |pmc=3218853 |pmid=21554751 |doi-access=free }}</ref><ref name="NASAmarble">{{cite web |date=1 November 2012 |title=Apollo Imagery – AS17-148-22727 |url=https://spaceflight.nasa.gov/gallery/images/apollo/apollo17/html/as17-148-22727.html |url-status=dead |archive-url=https://web.archive.org/web/20190420043021/https://spaceflight.nasa.gov/gallery/images/apollo/apollo17/html/as17-148-22727.html |archive-date=20 April 2019 |access-date=22 October 2020 |publisher=NASA}}</ref>]]Measurements of the force exerted by [[Earth's gravity]] can be used to calculate its [[mass]]. Astronomers can also calculate [[Earth mass|Earth's mass]] by observing the motion of orbiting [[satellite]]s. Earth's average [[density]] can be determined through gravimetric experiments, which have historically involved [[pendulum]]s. The mass of Earth is about {{val|6|e=24|u=kg}}.<ref name="AA">''M''<sub>E</sub> = 5·9722×10<sup>24</sup> kg ± 6×10<sup>20</sup> kg. "[http://asa.usno.navy.mil/static/files/2016/Astronomical_Constants_2016.pdf 2016 Selected Astronomical Constants] {{Webarchive|url=https://web.archive.org/web/20160215143441/http://asa.usno.navy.mil/static/files/2016/Astronomical_Constants_2016.pdf |date=2016-02-15 }}" in {{citation |title=The Astronomical Almanac Online |url=http://asa.usno.navy.mil/ |publisher=[[United States Naval Observatory|USNO]]–[[United Kingdom Hydrographic Office|UKHO]] |access-date=2016-02-18 |archive-date=2016-12-24 |archive-url=https://web.archive.org/web/20161224174302/http://asa.usno.navy.mil/static/files/2016/Astronomical_Constants_2016.pdf |url-status=dead }}</ref> The average density of Earth is {{val|5.515|u=[[Gram per cubic centimetre|g/cm<sup>3</sup>]]}}.<ref name="NASA">{{cite web |title=Planetary Fact Sheet |url=http://nssdc.gsfc.nasa.gov/planetary/factsheet/ |access-date=2 January 2009 |work=Lunar and Planetary Science |publisher=NASA |archive-date=24 March 2016 |archive-url=https://web.archive.org/web/20160324033129/http://nssdc.gsfc.nasa.gov/planetary/factsheet/ |url-status=live }}</ref>