What Keeps an Astronaut Awake at Night? Cosmic Rays

In space, astronauts see stars in more than one way. Ever since the 1960s, space travelers have reported seeing bright flashes of light even with their eyes closed.They're usually described as either bursts or streaks, and are most often white. They seem to be frequent, too, many astronauts complained of trouble sleeping because of the disruptive scintillations. The culprit seems to be cosmic rays, highly energetic particles emanating from far-off sources that are normally blocked by our