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This figure from the study shows the arrival directions (empty circles) of all >100 EeV cosmic rays observed by the Telescope Array during 13.5 years of operation. They’re spread around the sky, and no clustering around the highest energy event (thick circle) is evident. “Although we may have expected events with energies above 100 EeV to be clustered, the observed arrival directions above 100 EeV have an isotropic distribution,” the authors explain. Image Credit: Telescope Array.org