How old is the oldest slice of Earth's seafloor? The answer is more contentious than you would think. Today, we visit one of the most debated locations in the show: a small island off the Greenland shore named Akilia. Everything about these rocks has been contested, and we'll meet three scientists who form cornerstones of the debates.

Extra Credit: Watch something on an old CRT TV, or count tree rings in a stump.

In 1991, a mysterious, striped red and gray rock was discovered on a cold Greenland isle. Years later, this rock would rock the scientific world with multiple debates about the early oceans and life. What exactly is this rock, and why do we care? Stay tuned, and on the way, we’ll learn how scientists can officially argue with each other.

Extra Credit: Eat something with peanut butter and chocolate, or pet a large and a small dog.