Free Astronomy Magazine September-October 2019

SEPTEMBER-OCTOBER 2019 T here are dif- ferent types of lethal radiation sources within a typical galaxy: from the occa- sionally active galactic nucleus (illustration above) to the much more mod- est but frequent superficial erup- tions of stars (video on the side). Whatever the source, radia- tion always has a deleterious effect on any known lifeform that is more-or-less di- rectly exposed to its flow. [NASA] ries of radiation exposures that astronauts undergo in their careers, subjects are usu- ally exposed to single flows of greater overall intensity and much lower duration. Add to this the fact that studies of the pos- sible effects of space radiation on astro- nauts usually do not take into consideration the complex energy spectra and diverse ionic compo- sition of the space radia- tion environment, but are limited instead to assessing exposure to mono-energetic beams composed of restricted types of particles or even of just a single type. In contrast, space missions are faced with a hetero- geneous zoo of particles, all with very different energy levels. survivors of nuclear power plant accidents and atomic bombing. These forms of total body radiation at high dosages for short periods are not those typical for space flights. The same thing can be said for ani- mal experiments, where, to simulate a se-