In science textbooks, Earth looks like a round layer cake. There's a hard line between the liquid metal core and the putty-like rock mantle. But maybe that boundary is a little fuzzier than we previously thought. Strange, continent sized blobs rest on the dividing line. These blobs are leaching material from the Earth’s core, extending arms out into the mantle, and sending core material up and out through magmatic plumes.  No one's completely sure how it’s happening. On this week’s episode, host Samir Patel and writer Robin George Andrews dig into the ancient isotopic signatures that are helping us better understand the material bubbling up from the depths of our planet. This topic was covered in a recent story for Quanta Magazine. Each week on The Quanta Podcast, Quanta Magazine editor in chief Samir Patel speaks with the people behind the award-winning publication to navigate through some of the most important and mind-expanding questions in science and math. Audio coda courtesy of wildlife photographers Gudmann & Gyda