History of the Universe 4 - Formation of the Galaxies.
HISTORY OF THE UNIVERSE 4 - FORMATION OF THE GALAXIES.
The first generations of stars formed in clusters of a few million stars. By the time the universe was a billion years old gravity was pulling these clusters together forming larger groups of billions of stars. The first galaxies were born.
The universe was a fraction of it’s present size, so the forming galaxies collided more often than they do today. Small clusters merged forming larger collections of stars. Black holes formed in the centre of the clusters occasionally exploding into activity during a merger or collission. Huge amounts of energy were released producing what we know today as quasars.
The early universe was dynamic and chaotic. Collisions, explosions, new stars forming at a far greater rate than they do today. Through it all, stars were making heavy elements out of Hydrogen and then exploding. The concentration of the all important heavy elements continued to increase.
The expansion continued and by the time the universe was three billion years old things had settled down. The galaxies had grown, now containing hundreds of billions of stars. The expansion had caused galaxies to move further apart so mergers and collisions were less frequent. The universe had outgrown it’s tempestuous youth and was taking on the more mature form that we are familiar with today.
The gravitational attraction between the galaxies was trying to draw them together but the expansion of the universe was tending to pull them apart. A tug-of-war developed between the two forces resulting in a slow down of the expansion. The slow down was such that the universe might eventually stop expanding and collapse in on itself. While this process might take hundreds of billions of years it seemed that the fate of the universe was sealed.
The universe was not going give up. It would not return to the nothingness from which it came. It was about to play it’s trump card, hidden within the very fabric of space itself was a mysterious force which was about to be unleashed. This force would completely change the future of the universe.
© Matthew Wallace 2008
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