Blinding Flashes NASA Science

Gazing out of their space capsules, Apollo astronauts witnessed sights that humans had never before seen. They saw the breathtaking view of the Earth’s bright blue disc against the inky black of space. They saw the far side of the Moon. They also saw strange flashes of light inside their eyeballs! Since then, astronauts aboard Skylab, the Shuttle, Mir, and the International Space Station have all reported seeing these flashes. No need to call Agents Mulder and Scully of The X Files, though: what the astronauts are experiencing is space radiation zipping through their eyes like subatomic bullets. When a “bullet” strikes the retina, it triggers a false signal that the brain interprets as a flash of light.