Planets, composition

Origin of the bulk planet composition volatile delivery and terrestrial Mg/Si ratio... 

GIANT-PLANET FORMATION 1.17.6.1 Giant-planet Compositions... 

Differences in Bulk Planet Compositions and Major Reservoirs... 

There appears to be a correlation between the mass of the planets and the mass and composition of their atmospheres. Generally, only those planets of high mass were able to retain much of their atmospheres. Nitrogen, hydrogen, and helium are probably abundant, though not yet detected, on the heavier planets. Table 25-V also reveals a considerable range in the surface temperatures of the planets. The higher temperatures on the terrestrial planets also contributed to the loss of their atmospheres. 

Needless to say, the extreme difficulty we experience in probing the composition of the earth beneath us suggests that little is known about the inner composition of the planets. The evidence available is indirect (average density, sur-... 

As soon as we start this journey into the atom, we encounter an extraordinary feature of our world. When scientists began to understand the composition of atoms in the early twentieth century (Section B), they expected to be able to use classical mechanics, the laws of motion proposed by Newton in the seventeenth century, to describe their structure. After all, classical mechanics had been tremendously successful for describing the motion of visible objects such as balls and planets. However, it soon became clear that classical mechanics fails when applied to electrons in atoms. New laws, which came to be known as quantum mechanics, had to be developed. 

The composition of the Earth was determined both by the chemical composition of the solar nebula, from which the sun and planets formed, and by the nature of the physical processes that concentrated materials to form planets. The bulk elemental and isotopic composition of the nebula is believed, or usually assumed to be identical to that of the sun. The few exceptions to this include elements and isotopes such as lithium and deuterium that are destroyed in the bulk of the sun s interior by nuclear reactions. The composition of the sun as determined by optical spectroscopy is similar to the majority of stars in our galaxy, and accordingly the relative abundances of the elements in the sun are referred to as "cosmic abundances." Although the cosmic abundance pattern is commonly seen in other stars there are dramatic exceptions, such as stars composed of iron or solid nuclear matter, as in the case with neutron stars. The... 

Effects of condensation are also seen in the bulk compositions of the planets and their satellites. The outer planets, Uranus and Neptune, have overall densities consistent with their formation from icy and stony solids. The satellites of Uranus have typical densities of 1.3g/cm which would tend to indicate a large ice com-... 

A collision with a Mars-sized object may have resulted in the formation of the Earth s moon. Our moon is by no means the largest satellite in the solar system, but it is unusual in that it and the moon of Pluto are the largest moons relative the mass of the planets they orbit. Geochemical studies of returned lunar samples have shown that close similarities exist between the bulk composition of the moon and the Earth s mantle. In particular, the abimdances of sidero-... 

The Earth is a highly unusual planet because life did evolve on it and it thrived to the extent that the surface and atmosphere of the planet were greatly modified. The Earth is unique in this respect relative to all known astronomical bodies (Taylor, 1999). The Earth s location, composition, and evolutionary history are all significant factors in the planet s success in nurturing life. Critical factors include its temperature, its atmosphere, its oceans, its long-term stability and its "just right" abundance of water and other light element compounds. 

Our planet Earth contains significant amounts of elements all the way up to Z = 92. This indicates that our solar system resulted from the gravitational collapse of a cloud of matter that included debris from second-generation stellar supemovae. Thus, our sun most likely is a third-generation star. The composition of a third-generation star includes high-Z nuclides, but the nuclear reactions are the same as those in a second-generation star. 

C22-0022. Describe how the compositions of planets around a second-generation star differ from that of the Earth. Could life as we know it exist on such a planet Why or why not ... 

Elderfield, H. and Schultz, A. (1996) Midocean ridge hydrothermal fluxes and the chemical composition of the ocean. Anna. Rev. Earth Planet. Sci. Lett., 24, 191-224. 

Edmond, J., Measures, C., McDuff, E. et al. (1979) Ridge crest hydrothermal activity and the balances of major and minor elements in the ocean The Galapagos data. Earth Planet. Sci. Lett., 46, 1-18. Elderfield, H. and Schultz, A. (1996) Midocean ridge hydrothermal fluxes and the chemical composition of the ocean. Annu. Rev. Earth Planet Sci. Lett., 24, 191-224. 

Ceding, T.E. (1984) The stable isotopic composition of modem soil carbonate and its relationship to climate. Earth Planet. Sci. Lett., 71, 229-240. 

The miniaturized Mossbauer instruments have proven as part of the NASA Mars Exploration Rover 2003 mission that Mossbauer spectroscopy is a powerful tool for planetary exploration, including our planet Earth. For the advanced model of MIMOS II, the new detector technologies and electronic components increase sensitivity and performance significantly. In combination with the high-energy resolution of the SDD, it will be possible to perform XRF analysis in parallel to Mossbauer spectroscopy. In addition to the Fe-mineralogy, information on the sample s elemental composition will be obtained. 

Oversby VM, Gast PW (1968) Lead isotope composition and uranium decay series disequilibrimn in recent volcanic rocks. Earth Planet Sci Lett 5 199-206... 

O Hara MJ (1968) The bearing of phase equilibria studies in synthetic and natural systems on the origin and evolution of basic and ultrabasic rocks. Earth Sci Rev 4 69-133 O Nions RK, McKenzie D (1993) Estimates of mantle thorium/uranium ratios from Th, U and Pb isotope abundances in basaltic melts. Phil Trans Royal Soc 342 65-77 Oversby V, Gast PW (1968) Lead isotope compositions and uranium decay series disequilibrium in reeent volcanic rocks. Earth Planet Sci Lett 5 199-206... 

Sturm ME, Goldstein SJ, Klein EM, Karson JA, Mnrrell MT (2000) Uranium-series age constraints on lavas from the axial valley of the Mid-Atlantic Ridge, MARK area. Earth Planet Sci Lett 181 61-70 Sun S, McDonongh WF (1989) Chemical and isotopic systematics of ocean basalts implications for mantle composition and processes. In Magmatism in the Ocean Basins. Saunders AD, Norry MJ (eds) Blackwell Scientific Pnbl. Oxford, p 313-345... 

Griffiths RW (1986) The differing effects of compositional and thermal buoyancies on the evolution of mantle diapirs. Phys Earth Planet Inter 43 261-273... 

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