We all know the Sun produces U.V. rays and that if you spend too much time sunbathing, you’ll probably get skin cancer. Well, the Sun spews a lot of other stuff into space too. Ultraviolet radiation may be the least of your worries if you happen to live in space.
In addition to U.V. rays, the Sun also produces:
- X-rays: sort of like U.V. rays, only with more energy and, therefore, more harmful.
- Gamma rays: even more energetic and harmful than X-rays.
- Solar ejecta: solar flares and other nasty explosions on the Sun can accelerate protons, electrons, and other little bits and pieces of atoms to ludicrous speeds. Do not stand in their way!
Fortunately, Earth’s atmosphere and magnetic field protect us from most of the Sun’s deadly radiation. Even the crew of the International Space Station are in a low enough orbit that Earth still keeps them safe. Well, safe-ish.
But all this radiation makes human space exploration beyond low Earth orbit extremely hazardous. Before sending astronauts to the Moon, NASA had to wrestle with their collective conscience over how much radiation exposure should be considered acceptable. Now, NASA is wrestling with its conscience again as it plans to send astronauts to Mars.
Current technology cannot protect humans from solar radiation. The problem gets worse with increased solar flare activity. One of the things science fiction writers (like myself) have to figure out is how to keep our characters from dying of radiation sickness within the first few chapters of our books.
P.S.: Starlight can kill you too. In addition to solar radiation, astronauts have to worry about cosmic radiation: radiation from other stars, quasars, and God knows what else.