Well....... Technically. Cosmic rays are spontaneous flashes of light that astronauts usually see while in space. Researchers think that think that astronauts see them because cosmic particle pass through part of the astronauts eyes called the vitreous humor. the color differs because everyone is different. Some of them say its just a pure flash of white light or its blue with a white cast. there are some rare cases where they reported it to be pale green or yellow.