Its observation was a shock to astrophysicists (hence the name), who estimated its energy to be approximately 3×1020 eV or 3×108 TeV. This is 20000000 times more energetic than the highest energy measured in electromagnetic radiation emitted by an extragalactic object[3] and 1020 (100 quintillion) times the photon energy of visible light.
The particle had a kinetic energy of 48 joules, equivalent to a 142-gram (5 oz) baseball travelling at about 26 m/s (94 km/h; 58 mph). "