Author: Richard Smith

<p>The question sounds almost too simple. You’ve got some cash tucked in a drawer, maybe a few folded bills in an envelope behind a book on the shelf. Is that enough? Is it too much? Should it be in a fireproof safe, or should it not be at home at all? Most people have never…</p>

<p>Buried deep within Earth’s mantle, two mysterious “supercontinent”-sized structures, known as Large Low-Shear-Velocity Provinces (LLSVPs), may be nearly as ancient as the planet itself. No drill has ever reached them. No human eye has ever seen them. And yet, over the past several decades, they have emerged as perhaps the most geologically consequential features on…</p>