In the ultimate test of nature's 'radiation tolerance,' Deinococcus radiodurans reigns supreme. This micro-organism possesses a mind-boggling capability: it can survive an ionizing radiation dose of up to 15,000 Gray (Gy) without losing its viability.

To put this defensive prowess into perspective:

• Human Limit: A mere 5 to 10 Gy is enough to be fatal to an adult human.
• Stark Contrast: D. radiodurans is 1,500 to 3,000 times more radiation-resistant than humans. It makes even the resilient microbes found in the Chernobyl reactor core look fragile by comparison.

Often dubbed the 'Conan the Bacterium,' its secret lies in an extraordinarily efficient DNA repair mechanism. It can reconstruct its shattered genome like a high-speed jigsaw puzzle within hours of being bombarded. This unique trait has even led scientists to propose it as a potential candidate for carrying biological information across the stars.