::Core (geology)




Not to be confused with planetary core in the core accretion theory, referring to a central accretionary body surrounded by a halo of dust and gas which serves to trap debris and increase the rate of accretion.
The internal structure of the inner planets.

The planetary core consists of the innermost layer(s) of a planet; which may be composed of solid and liquid layers.<ref name="sci.1112328">{{#invoke:Citation/CS1|citation |CitationClass=journal }} </ref> Cores of specific planets may be entirely solid or entirely liquid.<ref name="Williams and Nimmo 2004">{{#invoke:Citation/CS1|citation |CitationClass=journal }}</ref> In our solar system, core size can range from about 20% (Moon) to 85% of a planet's radius (Mercury).

Gas giants also have cores, though the composition of these are still a matter of debate and range in possible composition from traditional stony/iron, to ice or to fluid metallic hydrogen.<ref name="Pollack, et al. 1977">{{#invoke:Citation/CS1|citation |CitationClass=journal }}</ref><ref name="Fortney and Hubbard 2003">{{#invoke:Citation/CS1|citation |CitationClass=journal }}</ref><ref name="Stevenson 1982">{{#invoke:Citation/CS1|citation |CitationClass=journal }}</ref> Gas giant cores are proportionally much smaller than those of terrestrial planets, though theirs can be considerably larger than the Earth's nevertheless; Jupiter has one 10-30 times heavier than Earth,<ref name="Stevenson 1982" /> and exoplanet HD149026 b has a core 67 times the mass of the Earth.<ref name="Sato, et al. 2005">{{#invoke:Citation/CS1|citation |CitationClass=journal }}</ref>

Core (geology) sections