Planets and Satellites

As stated earlier, many shock reactions would have proceeded in the solar system, and much research relevant to the processes has been published. In this section, two examples of the well-studied cases—chemical evolution of Earth and Titan—are reviewed. 

Chemical Role of Impact Shocks on Terrestrial Planets 

Large impactors bombarded early Earth at the same time that large impact basins formed on the Moon [66,73]. Impact-induced shock waves associated with the projectile bombardments would have played an important chemical role on early Earth. The role has been discussed particularly in relation to the origin of life. 

Roles of impact shocks controlling the chemical environments of Earth, in particular, atmosphere, hydrosphere, and biosphere, are summarized as follows 1) devolatilization and erosion of atmosphere, 2) production of organic materials, and 3) delivery of materials. 

Depletion of rare gases in Earth s atmosphere in comparison with cosmic abundances suggests that any primary atmosphere captured at the planet s early accretion could have been lost by an impact with one or more large bodies during the later stages of the accretion [66,74], and by T-tauri solar winds of high-energy particles which could readily blow volatile elements out of the inner Solar System [75]. 

The best classification of the development of planetary research is due to Kuiper, the father of modern planetology, who distinguishes three phases  

the three centuries of basic, classical discoveries (Galilei, Kepler, Laplace et al.). 

The second phase, beginning at the end of the nineteenth century, was linked to the development of astrophysics and astrophotography this phase was, however, marked by a decrease in scientific interest in planetary research. 

Phase three, the renaissance of planetology, starting around 1960, caused in particular by the rapid development and successes of space travel. 

In this chapter, we will deal particularly with those planets and moons which are relevant to the question of the origin of life. 

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Observe the chemical composition of the atmospheres and surfaces of comets, planets and satellites. 

The sun, the planets and satellites like the moon were formed 4.5 Gyr ago as a consequence of gravitational instability in a part of a dense interstellar cloud. This particular dense insterstellar cloud no longer exists for obvious reasons, but other dense interstellar clouds can still be observed in our galaxy. Some of these dense... 

Kasting, J.F. 1990. Bolide impacts and die oxidation state of carbon in the Earth s early atmosphere. Origins Life 20 199-231. See also Schaefer, L., and Fegley Jr., B., 2007, Outgassing of ordinary chondritic material and some of its implications for the chemistry of asteroids, planets, and satellites, Icarus 186.2 462-483. 

Kuiper s list of astronomical accomplishments is impressive. In addition to his work on binary stars, the atmospheres of planets and satellites, and the formation of the solar system, he discovered the fifth moon of Uranus, Miranda, and Neptune s second moon, Nereid he was an early advocate of the use of jet airplanes for high-altitude astronomical observations and he accurately predicted the nature of the lunar surface before any human had walked on it. In recognition of these achievements, Kuiper was awarded the Janssen medal of the French astronomical society and the Order of Orange Nassau by the Dutch government. Kuiper died in Mexico City on December 24,1973, while examining a number of possible sites for a new observatory. 

Message, P.J. and Taylor, D.B. (1978) On asymmetric periodic solutions of the plane restricted problem of three bodies, and bifurcations of families. In Szebehely, V., editor, Dynamics of planets and satellites and theories of their motion (Proceedings of Symposium No. fl of the International Astronomical Union), pages 319-323. Message, P.J. (1980) On the existence of periodic solutions of Poincare s second sort in the general problem of three bodies moving in a plane. Celestial Mechanics, vol. 21, pages 55-61. 

Not only do meteorites give us information on genetic and evolutionary processes of and in their parent bodies, some meteorites contain materials predating Solar System formation. Thus meteorites contain unique information on pre-Solar conditions, condensation processes within the Solar System, in the inner part where liquid water could have existed, and the present-day status of the Sun and its planets and satellites. Meteorites are unique in that they contain chronometers that allow the various genetic episodes that affected them to be dated. 

Physical and Photometric Data for Planets and Satellites 74 Ed. Related data included in 90 Ed., p. 14-2,14-4... 

The chemistry of planetary atmospheres is now a well-established discipline in which studies of any one planet enhance our understanding of them all. Chemical processes dominate the evolution of the atmospheres of the planets, determine the nature of the clouds and the composition of the oceans and are the major source of the escaping atoms and ions that occupy the space between the planets and satellites. 

The range of characteristics of planets is likely to exceed our experience with the planets and satellites in our own Solar System by far. Models of planets more massive than our Earth - rocky Super-Earths - need to consider the changing atmosphere structure, as well as the interior structure of the planet. Also, Earthlike planets orbiting stars of different spectral type might evolve differently. Modeling these influences will help to optimize the design of the proposed instruments to search for Earth-like planets. 

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