Editing Planetary core (section)

=== Core heat source ===
A planetary core acts as a heat source for the outer layers of a planet. In the Earth, the heat flux over the core mantle boundary is 12 terawatts.<ref name="nimmo 2015">{{Cite book |last=Nimmo |first=F. |url=https://linkinghub.elsevier.com/retrieve/pii/B9780444538024001391 |title=Treatise on geophysics |date=2015 |publisher=[[Elsevier]] |isbn=978-0-444-53803-1 |location=Amsterdam |pages=27–55 |chapter=Energetics of the Core |doi=10.1016/b978-0-444-53802-4.00139-1}}</ref> This value is calculated from a variety of factors: secular cooling, differentiation of light elements, [[Coriolis force]]s, [[radioactive decay]], and [[latent heat]] of crystallization.<ref name="nimmo 2015" /> All planetary bodies have a primordial heat value, or the amount of energy from accretion. Cooling from this initial temperature is called secular cooling, and in the Earth the secular cooling of the core transfers heat into an insulating [[silicate]] mantle.<ref name="nimmo 2015" /> As the inner core grows, the latent heat of crystallization adds to the heat flux into the mantle.<ref name="nimmo 2015" />