Conan the Bacterium. That’s the playful name given by biologists to an organism whose official moniker is “Deinococcus radiodurans.” D. radiodurans is microscopic, but that doesn’t mean it’s a pushover. It can take heat, cold, long periods of desiccation. In fact, D. radiodurans is so tough that you can’t even kill it with intense radiation–almost a sure-kill treatment for living things. Let’s use ourselves as an example. Very high-energy photons are called “gamma rays,” and they are measured in rads. Moderate energy photons, such as those coming from the sun and landing on you right now, aren’t too dangerous. Gamma rays, however, are another matter. About one thousand rads of gamma rays will kill a person.