The big bang theory originated form one huge mass of densely packed matter. The densely packed matter violently exploded with a “big bang” send out matter and energy in all directions. From this matter stars and galaxies now exist.
Red Shift Galaxies are moving further apart from each other. When a star moves away the wavelengths of light appear elongated. If a galaxy is moving away from the Earth, its wavelengths of light are shifted to the red end of the spectrum. If a galaxy is moving closer to the Earth then the blue end of the spectrum.