Here's the WP article on that OMG particle (one particle with the energy of a thrown baseball): https://en.wikipedia.org/wiki/Oh-My-God_particle

Since then, over 70 more like it have been seen; most seem to arrive from the Ursa Major direction, "from a distinct source near our galaxy and not from sources spread all over the universe." https://www.sciencemag.org/news/2014/07/physicists-spot-pote...