The glory of creation continued in its preset manner after the decoupling of radiation when the universe in the form of the expanding fireball cooled down from the unimaginably high level of 1026 K to a cool 3000 K. At this stage the universe was still a very simple, expanding ball of gas, 70% hydrogen, 29% helium, and 1% deuterium gas confined to a relatively small area with a radius of 12.47 × 105 light-years and a density of 6.8 × 10−22 g/cm3. Atoms heavier than helium did not exist. From here on, however, the universe grew continually more complex into protogalaxies, evolving later into galaxies. The principal evolution of matter took place much later in the cores of stars which condensed due to gravitational forces from galactic gas.
KeywordsBlack Hole Spiral Galaxy Elliptical Galaxy Solar Mass Gravitational Attraction
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