Spelling suggestions: "subject:"cosmology"" "subject:"osmology""
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Does the universe require a cause?Sickler, Bradley L. January 2002 (has links)
Thesis (M.A.)--Trinity International University, 2002. / Abstract. Includes bibliographical references (leaves 101-105).
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New cosmological modelShen, Po-Yu January 1970 (has links)
The present situation in cosmology is discussed. We try to explain the observed distribution of quasars in terms of an inhomogeneous model universe that consists of inner and outer Friedmann zones separated by a transition zone. The number - red-shift relation is derived, and numerical calculations are performed on the assumption that the transition zone is negligible. When the results are compared with observation, it is found that the dearth of quasars with red-shifts greater than 2 is easily explained, but that one cannot account for their anisotropic distribution. Modifications of the model are suggested. / Science, Faculty of / Physics and Astronomy, Department of / Graduate
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Rendering dark energy voidFebruary, Sean Phillip January 2009 (has links)
Includes abstract. / Includes bibliographical references (leaves 114-120). / The current model of cosmology, the Friedman-Lemaitre-Robertson-Valker model, assumes that the universe is approximately homogeneous and isotropic on very large scales. Further assuming flatness and dark energy in the form of Einstein's cosmological constant A then implies that the latter contributes roughly 73% of the total energy of the universe, cold dark matter (CD'I) 23SiC, and baryons, the matter we are made, only 4%.
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Probing primordial non-Gaussianity using large scale structureFantaye, Yabebal January 2009 (has links)
Includes abstract. / Includes bbliographical references (leaves 65-69). / Recent evidence from the WMAP satellite has lead to a tentative detection of non-Gaussianity. Using the bispectrum statistic applied to the MegaZ catalogue of over 600,000 luminous red galaxies we find new bounds on the large-scale nonGaussianity. We constrain the fNL parameter using a particular type of triangular configuration as well as the combination of all the possible triangles in harmonic space. The constraint on fNL from the combination of all possible triangular configurations is ffV'ial = 57 ± 52 with 68% confidence limit, which is consistent with vanishing primordial non-Gaussianity, although some triangular configurations on their own suggest a non-zero bispectrum which, if confirmed, would have a profound effect on modern cosmology.
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Probing the new cosmologyZentner, Andrew Ronald 06 August 2003 (has links)
No description available.
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Supernovae under the gravitational lensGunnarsson, Christofer January 2005 (has links)
<p>With general relativity as its foundation, the Standard Model of Cosmology has been developed, a model in which all matter is homogeneously and isotropically distributed throughout the Universe. We know for sure that this is not true since inhomogeneous structures such as galaxies, planets and synthesizers, are known to exist on small cosmological scales. However, on large scales the approximation of homogeneity is very good. Despite this, inhomogeneities such as galaxies or clusters of galaxies, will affect the propagation of light in the Universe by bending the paths of light-rays according to the laws of general relativity. The phenomenon is known as gravitational lensing. The bending of light-rays is similar to what happens in an optical lens, where an image of an object may be distorted or (de-)magnified depending on the shape of the lens.</p><p>Using the magnifying power of a gravitational lens it is possible to see further out in the Universe, it is used as a natural gravitational telescope. Under the right circumstances this can be something very useful. By studying light from supernovae, exploding stars, it is to some extent possible to gather information on the constituents of our universe. If for some reason this light is affected on its way to us, e.g. by gravitational lensing, we are mislead into drawing erroneous conclusions unless the lensing effects are under control and corrected for. Trying to control this and other systematic uncertainties is a big challenge in supernova cosmology and is also becoming more and more important as statistical errors are being beaten down to very low levels.</p>
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Supernovae under the gravitational lensGunnarsson, Christofer January 2005 (has links)
With general relativity as its foundation, the Standard Model of Cosmology has been developed, a model in which all matter is homogeneously and isotropically distributed throughout the Universe. We know for sure that this is not true since inhomogeneous structures such as galaxies, planets and synthesizers, are known to exist on small cosmological scales. However, on large scales the approximation of homogeneity is very good. Despite this, inhomogeneities such as galaxies or clusters of galaxies, will affect the propagation of light in the Universe by bending the paths of light-rays according to the laws of general relativity. The phenomenon is known as gravitational lensing. The bending of light-rays is similar to what happens in an optical lens, where an image of an object may be distorted or (de-)magnified depending on the shape of the lens. Using the magnifying power of a gravitational lens it is possible to see further out in the Universe, it is used as a natural gravitational telescope. Under the right circumstances this can be something very useful. By studying light from supernovae, exploding stars, it is to some extent possible to gather information on the constituents of our universe. If for some reason this light is affected on its way to us, e.g. by gravitational lensing, we are mislead into drawing erroneous conclusions unless the lensing effects are under control and corrected for. Trying to control this and other systematic uncertainties is a big challenge in supernova cosmology and is also becoming more and more important as statistical errors are being beaten down to very low levels.
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The experiential significance of landscape in the Shakespearean imaginationChamberlain, Paul Geoffrey 06 July 2018 (has links)
The application of literature to geographical research has been a matter of interest
to scholars since antiquity but, apart from several normative statements on this subject in the
past, literary geography has not been a serious focus of geographical inquiry until relatively
recently. Since the early 1970s, however, humanistic geographers have been probing
literature assiduously not simply for its geographical content, but for the subtle clues that it
provides in helping us to better understand the mundane, contradictory and transcendental
experiences of human beings in relation to their environment. It is upon the latter that this
research focuses. Specifically, the purpose of this study was to explore the experiential
significance of landscape in the Shakespearean imagination in the belief that by doing so we
can not only shed new light on the perceptions, attitudes and values of the culture in which
it was written, but also improve our own understanding of the world in which we live.
Although an enormous amount of research has been undertaken on William
Shakespeare, litterateurs have tended to ignore many aspects of the playwright’s work that
are so important to geography. In focusing upon Shakespeare’s dramatic landscape, I have
attempted to fill this gap.
First, I identify a wide variety of elements of the landscape according to their frequency of occurrence; then, through the application of phenomenology and hermeneutics, I have endeavoured to disclose the meaning of these elements as they are portrayed in the text; the application of polarity, ambiguity and antinomy, as well as the literary devices of symbolism, simile and metaphor have been used to enrich the discourse. My method of inquiry is superimposed upon a conceptual framework in which I first examine the landscape from the macroscale, focusing upon the cosmic landscape of Elizabethan cosmology, terrestrial space and the stage; then I approach the landscape from the mesoscale, by exploring the regional landscape of the city, the middle landscape and the wilderness; finally, I concentrate upon specific landscape elements within the regional landscape, by classifying them into either a territorial core, interactional space or public space. The study ends by identifying some important concepts from within the research framework and I elaborate upon these in an attempt to disclose more fully the experiential significance of landscape in the Shakespearean imagination.
One of the most important concepts identified in this study is the pervasive use of the body-landscape metaphor. However, the landscape:body metaphor is far more prevalent in Shakespeare's work, because the body:landscape metaphor did not become more widely adopted until much later in history. Nevertheless, Elizabethan cosmology is clearly reflected in the spatial representation of the landscape: the city is a symbol of order and a metaphor for paradise; the wilderness is a symbol of chaos and a metaphor for hell; and the middle landscape mediates between this antinomy. But there are some anomalies. The centre of the landscape periodically erupts in chaos, and the periphery harbours enclaves of order that are sometimes portrayed as utopias. In addition, even though the centre of the landscape is overwhelmingly portrayed as sacred--in contrast to the periphery, which is profane--in practice the antinomy of sacred and profane space is misleading, because the Elizabethans' whole life was encapsulated in an eschatological doctrine in which the entire world was sacred. Furthermore, the complexity of the Shakespearean landscape is displayed in a variety of responses to the human involvement with the environment that can best be understood when placed upon an insider-outsider continuum. Perhaps most significant of all, however, is the role of the stage. The symbolic representation of heaven and hell in the theatre not only allows the vertical metaphorical landscape of Elizabethan cosmology to interact with horizontal terrestrial space in ways that profoundly transform the landscape; there is strong evidence that this allowed the Elizabethan audience to view the theatre as a metaphor for life through a 'suspension of disbelief', giving them a sense of identity, purpose and meaning in a way that modern drama, and even cinematography, has found virtually impossible to emulate. / Graduate
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Cosmological test with the QSO Hubble diagramLópez-Corredoira, M., Melia, F., Lusso, E., Risaliti, G. 04 1900 (has links)
A Hubble diagram (HD) has recently been constructed in the redshift range
$0\lesssim z\lesssim 6.5$ using a non-linear relation between the ultraviolet and
X-ray luminosities of QSOs. The Type Ia SN HD has already provided a high-precision
test of cosmological models, but the fact that the QSO distribution extends well
beyond the supernova range ($z\lesssim 1.8$), in principle provides us with an
important complementary diagnostic whose significantly greater leverage in $z$
can impose tighter constraints on the distance versus redshift relationship. In
this paper, we therefore perform an independent test of nine different cosmological
models, among which six are expanding, while three are static. Many of these are
disfavoured by other kinds of observations (including the aforementioned Type Ia
SNe). We wish to examine whether the QSO HD confirms or rejects these earlier
conclusions. We find that four of these models (Einstein-de Sitter, the Milne
universe, the Static Universe with simple tired light and the Static universe
with plasma tired light) are excluded at the $>99\%$ C.L. The Quasi-Steady State
Model is excluded at $>95$\% C.L. The remaining four models ($\Lambda$CDM/$w$CDM,
the $R_{\rm h}=ct$ Universe, the Friedmann open universe and a Static universe
with a linear Hubble law) all pass the test. However, only $\Lambda$CDM/$w$CDM
and $R_{\rm h}=ct$ also pass the Alcock-Paczy\'nski (AP) test. The optimized
parameters in $\Lambda$CDM/$w$CDM are $\Omega _m=0.20^_$ and
$w_{de}=-1.2^_$ (the dark-energy equation-of-state). Combined
with the AP test, these values become $\Omega _m=0.38^_$ and
$w_{de}=-0.28^_$. But whereas this optimization of parameters
in $\Lambda$CDM/$w$CDM creates some tension with their concordance values,
the $R_=ct$ Universe has the advantage of fitting the QSO and AP data
without any free parameters.
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Reheating the universe in brane world cosmological modelsChoi, Wai-fung., 蔡偉峰. January 2007 (has links)
published_or_final_version / abstract / Physics / Master / Master of Philosophy
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