Tinkerbelle has been up to some mischief in space. Ever since the Apollo Missions, astronauts have reported seeing strange flashes of white or bluish white light. Astronaut Don Pettit once described them as “luminous dancing fairies.” Sadly, these fairies aren’t magic. They’re a sign of something rather dangerous.
In space, you can expect to see these fairies at any time. They’ll appear to flicker and flutter all around the interior and exterior of your spacecraft, but they’ll be most visible in the dark. And if you really want to get a good look at them, you should close your eyes.
You read that right. Close your eyes. This phenomenon is easiest to observe with your eyes closed… a fact which gives a pretty big hint about what’s really going on.
Cosmic radiation is ubiquitous. In space, cosmic rays are constantly passing through your body, steadily raising your cancer risk. Every once in a while, a cosmic ray will pass through your eye. When it does, it may trigger the rods and cones of your retina, or it may even hit your optic nerve directly. And that’s when you start seeing pretty lights.
So the next time you’re in space…
… close your eyes for a few minutes and count how many flashes you see. That’ll give you some sense of how much radiation you’re soaking up.
P.S.: According to this article from Universe Today, Apollo Mission astronauts saw on average one “fairy” every 2.9 minutes.