Solar system studies

Note that the cosmic-ray community uses a different half-life for 26A1 than the one used for early solar system studies. 

Comets are primitive but complex bodies that potentially contain solid materials from a wide sampling of the cold regions of the solar nebula disk. Comet formation appears to be a common consequence of star formation and studies of solar system comets provide important links between solar system studies and a broad range of astronomical investigations. Although the comets are undoubtedly the best preserved materials from the solar nebula, they have potentially been influenced and processed by a significant number of nebular and parent-body processes. The properties and mysteries of comets contain important clues to numerous materials, environments, and processes that occurred both in the cold regions of the solar nebula and in the environments that preceded it. 

As accurately as these calculations can be made, however, the behavior of celestial bodies over long periods of time cannot always be determined. For example, the perturbation method has so far been unable to determine the stability either of the orbits of individual bodies or of the solar system as a whole for the estimated age of the solar system. Studies of the evolution of the Earth-Moon system indicate that the Moon s orbit may become unstable, which will make it possible for the Moon to escape into an independent orbit around the Sun. Recent astronomers have also used the theory of chaos to explain irregular orbits. 

Message, P.J. (1999) Orbits of Saturn s satellites some aspects of commensurabilities and periodic orbits. In Steves, B., and Archie Roy, A.E., editors, The Dynamics of Small Bodies in the Solar System A Major Key to Solar System Studies (The Proceedings of the N.A. T. O. Advanced Study Institute, in Acquafredda di Maratea, Calabria, Italy, 1997.), pages 207-225. 

Froeschle, C. and Lega, E. (1999). Weak chaos and diffusion in Hamiltonian systems. From Nekhoroshev to Kirkwood, in the NATO/ASI series Vol. 522 The Dynamics of small bodies in the Solar system a major key to Solar system studies, A.E.Roy (eds.). 

A very wide range of astrophysical problems can be tackled with ISOCAM, for example - solar system studies structure of zodisM l bands and cometary trails, spectral maps of comets - interstellar matter and staff formation nature of 12 m emission of large molecules or grains, grain formation and destruction, interaction between supemovae and the interstellar medium... 

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 geological sciences are involved in studying the naturally occurring materials of the earth and solar system (i) to understand the fimdamental processes of crustal formation on earth and solar system evolution, and (2) to evaluate the crustal materials of potential economic value to man. Prior to the 1930 s, analyses were carried out exclusively using classical analytical techniques, with detection limits on the order of o.oi-o.i % (mass fraction). The number of elements contained in any sample could be as extensive as the periodic table, but very few of these could be determined. The development of instrumental techniques revolutionized the analysis of geochemical samples, beginning in the 1930 s. 

The two rare earth elements niobium (Nb) and tantalum (Ta) were the main subject of study in the investigation referred to. Both elements have very similar properties and almost always occur together in our solar system. However, the silicate crust of the Earth contains around 30% less niobium (compared to its sister tantalum). Where are the missing 30% of niobium They must be in the Earth s FeNi core. It is known that the metallic core can only take up niobium under huge pressures, and the conditions necessary for this may have been present on Earth. Analyses of meteorites from the asteroid belt and from Mars show that these do not have a niobium deficit. 

It is tempting to take a tour of the solar system, stopping off at each planet to look at the chemistry from the origin of the red colour in Jupiter s great red spot to the volcanic activity of Io, but this would be another book for each planet. Instead, we will generalise the study to the formation of Earth-like planets in order to focus on the possibilities for life. 

The careful study of at least five different carbonaceous chondrites establishes the fact that these meteorites contain carbon compounds of extraterrestrial origin and of great significance in chemical evolution. Their presence confirms that the chemical reaction paths producing biologically important monomer molecules occur in the far reaches of our solar system. 

The adjective space in the chapter title loosely means extraterrestrial and could include planetology, the study of other solid bodies in the solar system, such as Mars, Comet Halley, or asteroid Ceres. While MS is vital to all planetary exploration, these devices function much the same way as laboratory MS, except that they are remotely operated, use less power, and are considerably more expensive. But space can also have the more restricted meaning of outside the ionosphere of any planet, but inside the solar system, which will be the area discussed in this chapter. The properties and challenges of this region are very different from the lab, although the science turns out to be often the same. 

In a Rapra study both natural PP and HDPE were tested together with similar materials containing carbon black as a stabiliser. The carbon black containing materials showed essentially no change in tensile strength after 1,035 days exposure in the UK, 510 days in Australia and 200 days in various accelerated exposures using QUVA lamps (fluorescent tubes which stimulate the UV sector (<400 nm wavelength)) and Xenon arc equipment (which stimulates the solar system). 

Stable isotope analysis of Earth, Moon, and meteorite samples provides important information concerning the origin of the solar system. 8lsO values of terrestrial and lunar materials support the old idea that earth and moon are closely related. On the other hand three isotope plots for oxygen fractionation in certain meteoric inclusions are anomalous. They show unexpected isotope fractionations which are approximately mass independent. This observation, difficult to understand and initially thought to have important cosmological implications, has been resolved in a series of careful experimental and theoretical studies of isotope fractionation in unimolecular kinetic processes. This important geochemical problem is treated in some detail in Chapter 14. 

Readers not familiar with the story of how Nicholas Copernicus disrupted 1000 years of astronomical wisdom according to Ptolemy should study this history. Copernicus got it right with his heliocentric model of the solar system, but any "due diligence" by senior academics of his time would have concluded he was dead wrong. All academic establishments have a stake in maintaining the validity and relevance of the work that got them to the top of their professions. 

Solar system processes are also among the targets, because of the disappearance of this heterogeneity with the metamorphic grade of the meteorites. Studies of temperature and duration of metamorphism are still in their early stages (El Goresy et al. 1995 Huss 1997)... 

In summary, the extinct radioactivities which have a limited time of existence in the solar system, constrain the time interval between the late stages of stellar nucleosynthesis and the formation of the solar system. Some production may also occur within the solar system during active periods of the young Sun. There have been numerous studies about how this matter was added into the solar system as a late spike of about 10 solar masses of freshly stellar processed material or from constant production in the galaxy (Wasserburg et al. 1996 Goswami and Vanhala 2000 Russell et al. 2001). These models are refined constantly with the input of new data and will probably continue to evolve in the future. 

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