radiation, n.All

Light is electro-magnetic radiation

Marie Curie, the Nobel prize winning scientist who discovered radium, died of radiation poisoning.

Radiation can give you cancer, which can be identified by radiation, and that can be treated with radiation.

Astronauts are exposed to the same amount of radiation as 150 to 6,000 chest x-rays.

Astronauts often see random flashes of light in space, even through closed eyes - this is caused by cosmic rays passing through their eyes or optical nerves.