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Distance measurements in inhomogeneous cosmologies
2007 (English)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

When making a raytracing program for supernova Ia data for calculations of an inhomogeneous and anisotropic universe with a zero curvature over all, it may be found that the possible negative pressure, the so-called dark energy, that is the presumable cause for an assumed accelerating expansion of the universe, is an optical illusion. The observably faint distant supernovas could thus be a result of gravitationally distorted light rays curving through the inhomogeneous universe, lengthening the travel distance to the observer. The local curvature is taken into account when the light ray travels through space, bending its path according to gravitational lensing. Comparing the magnitude from the simulated light ray, from a 0.5x0.5 degree portion of the sky, with the best-fit-curve of real SN Ia data, we however only see a very small difference. Hence is the effect due to inhomogeneities not as significant as believed. Our results were plotted as magnitude as a function of redshift and compared with observational data from a group of scientists searching for high redshift supernova type Ia, called the supernova cosmology project. The search for answers to how the universe is behaving, and more importantly: ''why?'', are still not concluded. Just because our results do not show the anticipated values for a non-accelerating expansion of the universe, there are still many effects to investigate. The over- and under-densities influences the way we measure the light distances to us and can still be imitating the visual effects of an accelerating universe. Also, the inhomogeneity should effect the very expansion dynamics itself, which is a topic for future studies.

Place, publisher, year, edition, pages
Keyword [en]
Physics Chemistry Maths
Keyword [sv]
Fysik, Kemi, Matematik
URN: urn:nbn:se:ltu:diva-51663ISRN: LTU-EX--07/121--SELocal ID: 8dd48662-199d-4286-ac2f-fd8d0aed3fbfOAI: diva2:1025027
Subject / course
Student thesis, at least 30 credits
Educational program
Space Engineering, master's level
Validerat; 20101217 (root)Available from: 2016-10-04 Created: 2016-10-04Bibliographically approved

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