Remember when you were in grade school and your teacher told the whole class to “put your heads down and close your eyes?” You were probably bored by the forced rest, and you may have discovered that rubbing your closed eyes could produce some very interesting visual effects, including flashing lights resembling stars. Did you know there’s a scientific name for that? These often amazing, colorful patterns are called phosphenes.
I got to thinking about seeing “stars” and other related phenomena, when I saw a Tweet from the folks at the fun website OMGFacts. The Tweet said simply: “Astronauts can see stars with their eyes closed!” It turns out, according to the site, that NASA astronauts often report seeing frequent flashes of light during space travel even when their eyes are shut.
NASA scientists attribute what must a rather unsettling experience to cosmic rays, which travel unimpeded through space but are largely stopped by our atmosphere. They are small enough, the researchers tell us, to pass through space travelers’ eyelids. What happens next—what specifically causes the flashes—is not fully understood. It may be that the cosmic rays cause the eye’s vitreous humor to produce light, or perhaps the flashes are caused by a direct impact of the rays on the retina.
Now imagine being incarcerated alone in a pitch-black cell for months or years (not a pleasant prospect, I know, but please bear with me). You would think you wouldn’t “see” anything at all during that time, right? But that doesn’t seem to be the case. Like those astronauts, according to this source and others, “prisoners who are put in solitary confinement, with zero light, report seeing a ‘light show’ of sorts, appearing out of the darkness. While most find it difficult to describe its form, some have reported the ‘cinema’ lights forming human figures.” The “cinema” effect may be related to the psychological effects of prolonged duration in low or no-light situations. And, yes, this visual phenomenon is known in the literature as “Prisoner’s Cinema.”
And we’d certainly be remiss if we didn’t touch on the classic example of “seeing stars”—which is how boxers have long described what happens when they get knocked out. The phosphenes they see as the hit the canvas may result from the pressure of the boxing glove to the eye, or changes in blood pressure in the brain due to the impact.
A few words of caution on this topic:
- Never apply pressure to your eyes or rub them unnecessarily. You could hurt yourself!
- Please avoid getting locked up in a dark jail cell. That’s not healthy either.
- Try not to get knocked out. If you are a boxer, be sure you use the right protective equipment (not to mention the right amount of ducking and weaving).
- And very important: Seeing flashes, “stars” or anything else unusual can indicate a serious condition. Don’t ignore symptoms like that—have them checked out!
Bottom line: If you want to see stars, take a walk on a nice clear night and look up. (And if you want to see an artistic interpretation of what phosphenes look like, watch this video.