Observations of the Light Flash phenomenon in space Original Research Article

Light Flashes are abnormal visual sensations caused by the interaction of high energy particles with the human visual apparatus. They were originally predicted in 1952 and observed on almost every manned missions in space. From the 1970s to now a number of dedicated observations in space and on ground (using accelerator beams) in a controlled environment have been carried forth to study this phenomenon. The picture emerging from these measurements shows that different particles can cause flashes through more than on physical interaction, each with a different cross-section. For instance, trapped protons in the South Atlantic Anomaly could interact in the eye, producing a number of secondaries which in turn would give rise to the phosphene observation. Direct mechanisms suggested are the ionization and the Cherenkov effect caused by highly charged particles. These mechanisms are thought to occur with a higher probability but the number of occurrence is small due to the lower particle flux in space. In this work, we briefly summarize the observations and results obtained in more than 30 years of research in space and on ground focusing on the recent Sileye data.