Colloquium

The Fractal Nature of the Visible Universe

Professor Paul Coleman

Institute for Astronomy
University of Hawaii

Wednesday, September 13, 2006   4:00 p.m.  NSH 118

(Refreshments at 3:30 p.m. NSH 292)

 

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 talk will concentrate on the largest scales which can be probed in our universe with the analyses of positions of galaxies.  It has been known for some thirty years that the locations of galaxies on small scales is fractal.  At larger length scales the distribution is supposed to exhibit a "correlation length" and then become homogeneous - except for occasional fluctuations.  More data has shown that the fluctuations are anything but occasional, with structure evident on even the largest scales probed.  The speaker will present analysis with methods suited to fractal distributions and show that no correlation length has actually been observed. Analysis also indicates that when galaxy masses are considered, the distribution may be multi-fractal.  These conclusions have serious implications for many sub-fields in astrophysics today, from galaxy formation to the Robertson-Walker metric of spacetime.