Thesis (M.Sc.) - Cairo University - Faculty of Science - Department of Astronomy and Meteorology

The present work is oriented to analyse theoretically two space experiments which are Gravity Probe-B and Hafele and Keating aroundthe- world-clocks experiments. To achieve this goal, relativistic theories of gravity with non-vanishing torsion have been previewed.The analysis is carried out to explore the e ect of torsion on their results, if any. The method of applying the theory chosen is given in details with stressing on the interactions between torsion and spin or rotation. Interactions between torsion and spin or rotation have not been taken into account in the analysis of the experimental results.The e ects of the above mentioned interactions, on the results of the two experiments, are calculated in the context of the theory chosen. It is shown that in case of Hafele and Keating experiment the e ect of torsion on time di erence is equal to 1:15 ns. It can not be detected since this e ect is beyond the sensitivity of the apparatus of the experiment. It is also shown that in case of Gravity Probe-B the e ect of torsion have been predicted qualitatively and it have been detected using the apparatuses of the experiment

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