re: #80 Ojoe
Your cells think so when the nucleus fires out ionizing radiation.
Reminds me of the comments from the moon astronauts long ago. They would see flashes of light often (see “stars”) which came from alpha particles zipping through their eyeballs and triggering the optic cells.
The reason we don’t hear about that from the space station or the shuttle is that it is low enough orbit to be shielded by the earth’s magnetic field.