EXPANSION SPEEDS AND ACCELERATIONS OF THE UNIVERSE IN FIVE GENERAL COSMIC MODELS

Main Article Content

FADEL A. BUKHARI

Abstract

Four new cosmological quantities were introduced which are the horizon expansion speed, horizon expansion acceleration, horizon volume speed and horizon volume acceleration of the universe expansion. These quantities have been investigated in five general cosmic models. The distributions of the space expansion speed of the universe in these models decrease up to minimum values, then they increase slowly until Capture8.PNG Gyr, and hence rise appreciably faster. In the observed general model the minimum space expansion speed is atCapture9.PNG Gyr. However, the distributions of the horizon expansion speed of the universe in the general models continuously reduce with cosmic time. At the present time in the observed general model Capture10.PNG . On the other hand, the distributions of the horizon volume speed of the universe expansion surge slowly until  Capture11.PNG yr, afterwards they ascend more rapidly up to maximum values, and hence they decrease gradually towards zero. At the present time in the observed general model Capture12.PNG . While the maximum horizon volume speed is at Capture13.PNG Gyr. The distributions of the speed expansion acceleration of the universe in the general models exhibit steep rise towards  and remain very close to this value, then they increase very slowly up to  Gyr, then they rise more rapidly, however after Capture14.PNG Gyr they surge substantially faster. Nevertheless, the distributions of the horizon expansion acceleration of the universe in the general models display sharp ascension towards Capture15.PNG and stay so adjacent to this value hence after Capture16.PNG Gyr. Finally, the distributions of the horizon volume acceleration of the universe expansion in the general models reduce with time unit Capture17.PNG Gyr where they remain close to Capture18.PNG . At the present time in the observed general model Capture19.PNG . It is found that the four new cosmological quantities are strongly related to the distribution of the total pressure of the universe.

Keywords:
Expansion speed, acceleration, cosmological quantities, cosmic models

Article Details

How to Cite
BUKHARI, F. A. (2021). EXPANSION SPEEDS AND ACCELERATIONS OF THE UNIVERSE IN FIVE GENERAL COSMIC MODELS. Journal of Applied Physical Science International, 13(1), 38-58. Retrieved from https://www.ikprress.org/index.php/JAPSI/article/view/6600
Section
Original Research Article

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