FRACTALS AND THE UNIVERSE

Abstract

Many examples of fractal geometry are seen in the field of Astronomy, from nearby objects such as our Sun, to phenomena at intermediate length scales in our Galaxy such as the distribution of masers. This paper will give many examples of various length scales and finally concentrates on the largest scales which can be probed in our universe, with analyses of locations of galaxies. It has been known for some twenty years that the distribution of galaxies on small scales is fractal. This is seen in analyses which indicate that both galaxies and their clusters are power law correlated (a signature of fractal behavior). At larger length scales the distribution is supposed to exhibit a so-called correlation length and was thought to then become homogeneous—except for occasional fluctuations. More data and subsequent analysis have shown that these fluctuations are anything but occasional, as structures are seen to exist on length scales up to the maximum scales which can be probed with the new data. By reanalyzing the data, with methods that are particularly suited to fractal distributions, one finds no correlation length at all—indicating that the fractal structure may extend up to perhaps the largest length scales possible. Analysis also indicates that when galaxy masses are considered, the distribution may be multifractal. These conclusions have serious implications for many subfields in astrophysics today, from galaxy formation to the Robertson-Walker metric of spacetime.