If a star would be like a nucleus of the atom the Galaxy is like a cell of a living body. In a central bulge of the galaxy are hundreds billions stars like in a nucleus of the cell (depends on a sort) http://en.wikipedia.org/wiki/Genome
Galaxy has a halo like a cell's cytoplasm. The globular clusters of old stars moves in halo around a center similar to granular mitochondria with a prokaryotes genomes. Mitochondria contains some tenth of thousands atoms. A dominant role for mitochondria is a cellular respiration and energy production. The role of the globular clusters in galaxy is not fully explained still. Cells and galaxies grows till it reach a maturity. The mature galaxies are similar in size like cells. A galaxy breathes by supernovae collapse and explosion.
In a galaxy is a similar number of stars like atoms in a cell.
Galaxies create the galaxy clusters like a cells create organs (stomach, heart, kidney, liver, brain...) Galaxy clusters create an Universe's filament like a human body.
A human embryo in prenatal development reach in 5 week (3 weeks from fertilization) a length of 4 mm (0,1 g). It is mainly water (oxygen) and little hydro carbonate. It is about 10^22 atoms like our present Observable Universe.
In this age has an embryo ; a brain, heart, branchial arches, lung, neural tubes , eyes, ears, arms, legs. http://en.wikipedia.org/wiki/Timeline_of_p...tal_development
Development of the Universe needs very long time period. Is there a test field on the Earth to verify all future possibilities of the development ?