After a decades-long search, expert scientists at a Japanese university think they've finally hit on the secret identity of the element that makes up the final 5% of Earth's core. Unfortunately, it's not some kickass new compound or even something with a futuristic name: it's probably plain old silicon.
It's pretty tricky to study the solid sphere at the centre of our planet, because aside from the fact that we can't really go carving up the floating space ball we live on, the heat and pressure are higher than in Gordon Ramsay's kitchen at dinner time. Measuring around 1500 miles across, the core is mainly composed of iron (85%) and nickel (10%), but that last 5% has eluded us until now.
Luckily, Eiji Ohtani's team at Tohoku University in Sendai, Japan, are on hand to quash all our cool theories about what it could be. After lots of experiments replicating the conditions in the inner core, they've concluded that it's probably an alloy of iron, nickel and silicon. Prepare the kale smoothies: turns out we're a Silicon Planet. [AGU via BBC]