The Blind Men and the Elephant, or the Search for Origins of the Highest Energy Cosmic Rays

Pierre Sokolsky

Distinguished Professor and Dean Emeritus

Department of Physics & Astronomy, The University of Utah

Ultra-high energy cosmic rays are the most energetic particles known. Their origin and nature have been the subject of study for decades. They are rare, exceedingly so at the highest energies, and the methods available for their study are indirect. Historical experiments have given sometimes conflicting results on their composition, anisotropy and
energy distribution, adding to their elusivity.

The new generation of experiments, including the Telescope Array and Pierre Auger observatories as well as smaller experiments such as the one associated with IceCube are now beginning to give us a more coherent
and consistent picture.

Dr. Sokolsky will discuss these most recent results leading to the elucidation of the shape and nature of the “elephant”. There are surprises as well as remaining areas of contention. Could it be that it’s not an elephant at all?