50 years ago, cosmic rays may have caused Apollo astronauts to see lights

Excerpt from the May 12, 1973 issue of Science News

Apollo astronaut Buzz Aldrin on the moon in a spacesuit

Apollo astronaut Buzz Aldrin, shown here on the moon in 1969, was among the first astronauts to report seeing mysterious flashes of light. Those flashes, attributed to high-energy particles called cosmic rays traveling through the eye, are still a problem for modern astronauts.


Light flashes no danger for short space flightsScience News, May 12, 1973

The light flashes and streaks seen by [Apollo] astronauts have long been attributed to high-energy, heavy cosmic particles (HZE) passing through the eyes…. A new report … concludes that the particles are not a serious hazard for short trips to the moon or Earth-orbital missions such as Skylab.


The mechanism behind the flashes described by Apollo astronauts remains a mystery. Perhaps the particles, which are components of c­osmic rays, emit radiation as they pass through part of the eye. Or perhaps they trick nerve cells to create the illusion of light. However the flashes happen, they are still an issue for astronauts. In 2006, about 80 percent of NASA and European Space Agency astronauts reported experiencing the flashes. How the phenomenon impacts astronaut health after months or years in deep space is unclear. As NASA plans crewed missions to Mars and the moon, scientists are devising new ways to protect astronauts from radiation (SN: 7/4/20 & 7/18/20, p. 18), such as portable magnetic shields that can deflect cosmic rays.

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