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The layers of the Earth, a differentiated planetary body. In planetary science, planetary differentiation is the process by which the chemical elements of a planetary body accumulate in different areas of that body, due to their physical or chemical behavior (e.g. density and chemical affinities).
Infographic showing the theorized origin of the chemical elements that make up the human body. Astrochemistry is the study of the abundance and reactions of molecules in the universe, and their interaction with radiation. [1] The discipline is an overlap of astronomy and chemistry.
Jupiter has been estimated to shrink at a rate of approximately 1 mm/year by this process, [1] corresponding to an internal flux of 7.485 W/m 2. [ 2 ] The mechanism was originally proposed by Kelvin and Helmholtz in the late nineteenth century to explain the source of energy of the Sun .
Practical Astronomy with your Calculator, Peter Duffett-Smith. Cambridge University Press; 3rd edition 1988. Advanced/graduate level: Numerical Methods in Astrophysics: An Introduction (Series in Astronomy and Astrophysics): Peter Bodenheimer, Gregory P. Laughlin, Michal Rozyczka, Harold. W Yorke. Taylor & Francis, 2006.
The theory was initially proposed by Fred Hoyle in 1946, [1] who later refined it in 1954. [2] Further advances were made, especially to nucleosynthesis by neutron capture of the elements heavier than iron , by Margaret and Geoffrey Burbidge , William Alfred Fowler and Fred Hoyle in their famous 1957 B 2 FH paper , [ 3 ] which became one of the ...
In chemistry, a derivative is a compound that is derived from a similar compound by a chemical reaction.. In the past, derivative also meant a compound that can be imagined to arise from another compound, if one atom or group of atoms is replaced with another atom or group of atoms, [1] but modern chemical language now uses the term structural analog for this meaning, thus eliminating ambiguity.
A major source of differentiation is fractionation, an unequal distribution of elements and isotopes. This can be the result of chemical reactions, phase changes, kinetic effects, or radioactivity. [1]: 2–3 On the largest scale, planetary differentiation is a physical and chemical separation of a planet into chemically distinct regions. For ...
The remaining 4.9% [11] comprises all ordinary matter observed as atoms, chemical elements, gas and plasma, the stuff of which visible planets, stars and galaxies are made. The great majority of ordinary matter in the universe is unseen, since visible stars and gas inside galaxies and clusters account for less than 10% of the ordinary matter ...