Record energy of a giant shower

Abstract
According to a reliable (χ12=0.93 with 36 degrees of freedom) interpretation of the readings of all triggered detector stations in a giant shower, detected at the Yakutsk array on May 7, 1989 at 13 h 23 min Greenwich time, in terms of the quark-gluon strings model with the geomagnetic field taken into account, the energy of this shower was 3×1020 eV.