Now, this is neat: A superheavy element (Z=122, A=292, tentatively named "eka-Thorium" or "unbibium") which is relatively stable (t1/2 ≥ 108 yr) has been observed in nature, in natural Thorium samples. (It's called eka-Thorium because it would sit directly below Thorium on the periodic table; as a result, it's chemically very similar to Thorium, which means it can mix in to Thorium ores and stick there because it doesn't separate very easily)
This is a whole 30 atomic numbers above the next-largest naturally occurring element, Uranium. (Z=92, A=238) It's the first empirical proof that superheavy nuclei can actually exist and be stable.
Edit: Some history - the last time an element was discovered in nature was Francium (Z=87), which was discovered in 1939 by Marguerite Perey. It was thought highly likely that that would be the last time anyone ever did.
April 30 2008, 04:56:52 UTC 7 years ago
Of course, it'd rock even more if it was more common than 10^-12 relative to Th. Still, one wonders if the stuff can be refined.