Electrical charges associated with sky darkening and the Turin shroud

Sky darkness was considered as a real phenomena occurring during the Holy Crucifixion. In fact, it was evaluated as a process that occurred with the strong earthquake described by Synoptic Gospels at the time of Christ's death. The considered models suggested that sky darkness was due to atmospheric phenomena of dense cloud formation. As reported in recent works, such phenomena can be explained by the presence of air ionisation near the ground, which is able to modulate condensation nuclei at cloud altitudes. The presence of air ionisation also during aftershock periods, after strong earthquakes, suggested the Shroud could have been exposed to such ionisation. A question was raised regarding the action of such ions on the shroud touching a corpse, if it was able to accelerate the image formation.