Good story telling involves overcoming obstacles. In sci-fi, those obstacles can include aliens, robots, various anomalies in space or time… We forget that every cubic light-year of space is full of danger even before we start making stuff up.
In addition to normal background radiation, empty space is full of other dangerous particles like high-energy helium ions (alpha particles), high-energy electrons (beta particles), and high frequency photons (gamma rays). These particles spew out of stars constantly and often get trapped in the magnetic fields of our planet and solar system.
Despite all our technology, astronauts are exposed to that radiation every time they go into orbit; so much so that NASA has safety guidelines to limit exposure during any individual’s lifetime.
Here on Earth, we are protected by the ozone layer and Earth’s magnetosphere (and yet too much sunlight… ultra violet radiation… can still give you cancer). Without some similar protection, any brave explorer in deep space will die a slow and un-dramatic death. Below are links to PDF files from NASA about radiation in space.
Tomorrow, we’ll look at another obstacle out there in “empty” space.