Health threat from cosmic rays radiation resulting from particle interactions within the vitreous humor. This phenomenon has been replicated on Earth by scientists at various institutions. As the duration of the longest Apollo flights was less than two weeks, the astronauts had limited cumulative exposures and a corresponding low risk for radiation carcinogenesis. In addition, there were only 24 such astronauts, making statistical analysis of any potential health effects problematic. In the above discussion dose equivalents is units of Sievert (Sv) are noted, however the Sv is a unit for comparing cancer risks for different types of ionizing radiation. For CNS effects absorbed doses in
Electromagnetic radiation and health Electromagnetic radiation and health Electromagnetic radiation can be classified into two types: ionizing radiation and non-ionizing radiation, based on the capability of a single photon with more than 10 eV energy to ionize oxygen or break chemical bonds. Ultraviolet and higher frequencies, such as X-rays or gamma rays are ionizing, and these pose their own special hazards: see "radiation" and "radiation poisoning". By far the most common health hazard of radiation is sunburn, which causes over one million new skin cancers annually. Very strong radiation can induce current capable of delivering an electric shock to persons or animals. It can