Changes

[[File:Kepler22b-artwork.jpg|thumb|right|400px|Artistic sketch of [[Kepler-22b]], a recently discovered [[exoplanet]] with comparable mass (within 10 [[Earth mass|Earth masses]]) of the planet Earth.]]

[[File:Kepler22b-artwork.jpg|thumb|right|400px|Artistic sketch of [[Kepler-22b]], a recently discovered [[exoplanet]] with comparable mass (within 10 [[Earth mass|Earth masses]]) of the planet Earth.]]

The discovery of [[extrasolar]] Earth-sized planets has spurred inquiry regarding their potential for [[Planetary habitability|habitability]]. One of the generally agreed-upon (Noack and Breuer and references within)<ref name=Noack_Breuer_2014 /> requirements for a life-sustaining planet is a mobile, fractured [[lithosphere]] cyclically recycled into a vigorously convecting [[Mantle (geology)|mantle]], commonly known as [[plate tectonics]]. Plate tectonics provide a means of geochemical regulation of atmospheric particulates, as well as sequestration of carbon. This prevents “runaway greenhouse” scenarios that can result in inhospitable surface temperatures and vaporization of liquid surface water.<ref name=Kaltenegger_Sasselov_2010 /> There is not a clear academic consensus on whether Earth-like [[exoplanets]] have plate tectonics, but it is widely thought that the likelihood of plate tectonics on an Earth-like exoplanet is a function of planetary radius, initial temperature upon coalescence, [[insolation]], and presence or absence of liquid-phase surface water.<ref name="O'Neill_Lenardic">{{cite journal|last1=O'Neill|first1=C.|last2=Lenardic|first2=A.|title=Geological consequences of super-sized Earths|journal=Geophysical Research Letters|date=11 October 2007|volume=34|pages=1–4|doi=10.1029/2007GL030598|url=http://onlinelibrary.wiley.com/doi/10.1029/2007GL030598/full|accessdate=10 October 2014}}</ref><ref name=Valencia_etal>{{cite journal|last1=Valencia|first1=D.|last2=O'Connell|first2=R.J.|last3=Sasselov|first3=D.|title=Inevitability of Plate Tectonics on Super-Earths|journal=The Astrophysical Research Letters|date=20 November 2007|volume=670|pages=45–48|doi=10.1086/524012|url=http://iopscience.iop.org/1538-4357/670/1/L45}}</ref><ref name=VanSummeren_etal_2011>{{cite journal|last1=Van Summeren|first1=J.|last2=Conrad|first2=C.P.|last3=Gaidos|first3=E.|title=Mantle convection, plate tectonics, and volcanism on hot exo-earths|journal=The Astrophysical Journal Letters|date=20 July 2011|volume=736|pages=1–6|doi=10.1088/2041-8205/736/1/L15|url=http://iopscience.iop.org/2041-8205/736/1/L15}}</ref><ref name=Korenaga_2010>{{cite journal|last1=Korenaga|first1=J.|title=ON THE LIKELIHOOD OF PLATE TECTONICS ON SUPER-EARTHS: DOES SIZE MATTER?|journal=The Astrophysical Journal Letters|date=10 December 2010|volume=725|pages=43–46|doi=10.1088/2041-8205/725/1/L43|url=http://iopscience.iop.org/2041-8205/725/1/L43|accessdate=10 October 2014}}</ref>

The discovery of [[extrasolar]] Earth-sized planets has spurred inquiry regarding their potential for [[Planetary habitability|habitability]]. One of the generally agreed-upon (Noack and Breuer and references within)<ref name=Noack_Breuer_2014 /> requirements for a life-sustaining planet is a mobile, fractured [[lithosphere]] cyclically recycled into a vigorously convecting [[Mantle (geology)|mantle]], commonly known as [[plate tectonics]]. Plate tectonics provide a means of geochemical regulation of atmospheric particulates, as well as sequestration of carbon. This prevents “runaway greenhouse” scenarios that can result in inhospitable surface temperatures and vaporization of liquid surface water.<ref name=Kaltenegger_Sasselov_2010 /> There is not a clear academic consensus on whether Earth-like [[exoplanets]] have plate tectonics, but it is widely thought that the likelihood of plate tectonics on an Earth-like exoplanet is a function of planetary radius, initial temperature upon coalescence, [[insolation]], and presence or absence of liquid-phase surface water.<ref name="O'Neill_Lenardic"> O'Neill, C.; Lenardic, A. (11 October 2007). "Geological consequences of super-sized Earths". Geophysical Research Letters 34: 1–4. doi:10.1029/2007GL030598. Retrieved 10 October 2014.</ref><ref name=Valencia_etal>{{cite journal|last1=Valencia|first1=D.|last2=O'Connell|first2=R.J.|last3=Sasselov|first3=D.|title=Inevitability of Plate Tectonics on Super-Earths|journal=The Astrophysical Research Letters|date=20 November 2007|volume=670|pages=45–48|doi=10.1086/524012|url=http://iopscience.iop.org/1538-4357/670/1/L45}}</ref><ref name=VanSummeren_etal_2011>{{cite journal|last1=Van Summeren|first1=J.|last2=Conrad|first2=C.P.|last3=Gaidos|first3=E.|title=Mantle convection, plate tectonics, and volcanism on hot exo-earths|journal=The Astrophysical Journal Letters|date=20 July 2011|volume=736|pages=1–6|doi=10.1088/2041-8205/736/1/L15|url=http://iopscience.iop.org/2041-8205/736/1/L15}}</ref><ref name=Korenaga_2010>{{cite journal|last1=Korenaga|first1=J.|title=ON THE LIKELIHOOD OF PLATE TECTONICS ON SUPER-EARTHS: DOES SIZE MATTER?|journal=The Astrophysical Journal Letters|date=10 December 2010|volume=725|pages=43–46|doi=10.1088/2041-8205/725/1/L43|url=http://iopscience.iop.org/2041-8205/725/1/L43|accessdate=10 October 2014}}</ref>

==Potential exoplanet geodynamic regimes==

==Potential exoplanet geodynamic regimes==