Theoretical cosmology

It is common practice in theoretical cosmology to rationalize illogical conclusions by mentioning the alleged probabilistic nature of quantum systems, out of context. 

The mass of the universe is in general evenly distributed it acts as Einstein s cosmological constant and accelerates expansion. Poor Agrees well with most of the recent measurements, but the evidence is still thin, and theoretical problems are still unsolved. 

The existence and distribution of the chemical elements and their isotopes is a consequence of nuclear processes that have taken place in the past in the Big Bang and subsequently in stars and in the interstellar medium (ISM) where they are still ongoing. These processes are studied theoretically, experimentally and obser-vationally. Theories of cosmology, stellar evolution and interstellar processes are involved, as are laboratory investigations of nuclear and particle physics, cosmo-chemical studies of elemental and isotopic abundances in the Earth and meteorites and astronomical observations of the physical nature and chemical composition of stars, galaxies and the interstellar medium. 

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. 

However, in emphasizing these aspects of the subject, we have neglected numerous broad fields in the realm of thermodynamics. Even within the areas to which we have limited ourselves, we have omitted any discussion of surface reactions [1], and we have paid only brief attention to problems of phase equilibria [2] and to electrochemical processes [3]. We also could have examined some topics of more theoretical interest, such as relativity and cosmology [4]. Similarly, we could have considered phase equilibria at high temperature and pressure [5]. 

This correction plays a key role in any cosmological application. Without it, SNIa events could not be used as distance indicators. However, its purely empirical nature remains unsatisfactory to demanding theoretical minds. We would like to be able to explain physically why some explosions are weaker than others, and what effect this has on the appearance of the object. This involves building detailed models of these explosions and the way radiation is hansferred through the expanding envelope, similar to those made to describe atomic bombs or spheres struck by laser beams, which implode before exploding. 

Recently it has been suggested that neutrinos have nonvanishing mass from both experimental and theoretical investigations. Accelerator experiments and cosmology, however, impose the constraints on... 

As pointed out by M. Turner (University of Chicago), a massive, neutrino would violate every theoretical prejudice we have in particle physics, astrophysics, and cosmology J. Bahcall (Institute of Advanced Study at Princeton) observes, It s a surprise. If it s true, tlien it s pointing us in a different direction than previous physics suggested, ... 

In the early sixties the problem of the beginning of cosmological expansion was deeply theoretical and far from verification by observation. Ya.B. persistently supported the search for methods of experimental verification of the question of whether the Universe was cold or hot in the early stages of its evolution. At first, Ya.B. sought an alternative to the hot model (1962) [25 ]. 

The years have no power over Ya. B. Zeldovich. He continues to work with youthful ardor. Lately he pays more attention to cosmology, but because of old attachments he directs the Scientific Council of the AS USSR on the problem of Theoretical Foundations of Combustion Processes. ... 

N. Cufaro-Petroni and J. P. Vigier Stochastic interpretation of relativistic quantum equations, in A. van der Merwe (Ed.), Old and New Questions in Physics, Cosmology, Philosophy, and Theoretical Biology Essays in Honor of Wolfgang Yourgrau, ISBN 0-20-640962-3, Plenum, New York, 1983, pp. 325-344. 

Figure 10.2. A sample of theoretical power spectra for various cosmological parameters, as marked.

Among the questions of importance to cosmology are the elemental composition of stars and other galactic matter and the isotopic compositions of those elements. Investigations of this type have covered several decades and represent a nice collaboration between theoretical astrophysicists and mass spectrometrists [80]. Thermal ionization has played a role in analysis, both isotopic and, through isotope dilution, of-concentration, of many of the elements and helped resolve some of the anomalies that were present in the, results of early work. Isotope dilution is inherently a precise method of quantification and was able to reduce... 

Schramm wanted to find out if the abundances of the light elements were consistent with big bang cosmology. To answer this question, he would need to refine theoretical predictions based on the tenets of big bang cosmology, design and carry out astronomical experiments to measure the abundances of the four light elements, and compare the results. As we shall see, the results for deuterium are particularly important—deuterium abundance depends on one and only one important parameter the density of matter. 

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