In the movies, radiation kills either instantly or slowly: immediate immolation, or a death from cancerous after-effects a few years down the line.
In reality, it's far stranger. You become, for a while, a "walking ghost."
Let's say you take a moderately large dose of ionizing radiation. You'll feel pretty sick for an hour or so. And then, against all expectations, you'll start to feel better. You might even be able to get up and walk around. Joke with your friends. Call your family.
For hours, even days, you'll feel pretty okay.
And then, one by one, over the next few weeks, your body's systems will begin to shut down.
Radiation damage primarily affects a cell's ability to divide. It messes with your DNA; that's why radiation causes genetic mutations and cancers.
So as long as you don't need any new cells, you're fine. Your current cells will work well enough for a few days. Like Wile E. Coyote hanging in mid-air after running off the cliff's edge, you'll be okay... as long as you don't do anything.
Sadly, that's not the way your body works. It needs replacement cells. It needs new red blood cells, skin cells, bone cells. Stomach cells. Nerve cells. Muscle cells.
And after a big dose of radiation, your body simply won't be able to make any more.
So you'll walk around for a while, feeling okay. Maybe even hoping it was just a bad dream. You can't see or smell or feel radiation, after all. Did you imagine it?
A walking ghost, wandering around a world not meant for you.
And then, one by one, without any new cells, your organs will quietly shut down.
Want to know more? Read about Hisashi Ouchi, the longest-surviving "walking ghost" on record. But be warned: the photos are not for the faint of heart.
And are you fascinated by unseen, undetectable, yet nevertheless lethal horrors? Try HASTUR - it has them all!