Apollo astronauts trying to sleep on the way to the Moon kept seeing flashes and streaks in the dark, and the cause turned out to be cosmic rays from deep space passing straight through their eyes.
Space Daily • • general
Key Points:
- Apollo astronauts reported seeing brief flashes and streaks of light in the dark during missions to the Moon, later identified as phosphenes caused by cosmic rays passing through their visual system.
- Experiments on Apollo 16 and 17 matched some reported flashes to heavy cosmic-ray particles passing through the eye, confirming cosmic rays as the cause of these visual sensations.
- The exact biophysical mechanism behind how cosmic rays produce these flashes remains uncertain, with theories including direct ionization of retinal tissue, Cherenkov radiation, and stimulation of the optic nerve or brain.
- These flashes highlight the reality of cosmic radiation exposure beyond Earth's protective atmosphere and magnetic field, raising concerns about its effects on astronauts' brains during long-duration deep space missions.
- Future lunar and deep space missions, such as those under Artemis, will likely observe these flashes again, with improved instruments aimed at better understanding the impact of cosmic radiation on the central nervous system.