Around 20 terrawatts of heat, which is about double what us humans use, originates from decaying radioactive materials such as potassium, uranium and thorium. The energy released from these materials is so powerful that they can move mountains, according to research undertaken in Japan and Italy. [Scientific American]
Time to nip this one in the bud.
Attention all trolls: I know it doesn't happen very often, but once in a while a Gizmodo writer doesn't stray from the facts—and Kat has the facts on her side here. Go read the linked article—it references peer-reviewed journals. Those are more credible than any crap you can spam in here from Wikipedia.
And I'm not dissing Wikipedia, per se. Wikipedia may have facts—but when you spam them out of context nor the expertise to interpret them, you fail.