Earth's mysterious core may be encased by an ancient ocean floor that has mountains 5 times taller than Everest

There's a lot we still don't know about our planet's core, which lies about 1,800 miles beneath our feet. Now, a new study has revealed a discovery that could help researchers piece together its mysterious inner workings. The research suggests that Earth's core could be encased in an ancient ocean floor that features giant mountains five times the size of Mount Everest. Researchers made the discovery after creating the most detailed map yet of the geology beneath our planet's southern hemisphere. If confirmed, this "recycled" ocean floor would act almost like a "blanket" that keeps heat trapped inside the core, Samantha Hansen, study lead author and geological sciences professor of the University of Alabama, told Insider in an email.

Scientists have long been confused by the boundary between the mantle and the core. About 2,000 miles under the Earth's surface, conditions shift dramatically: temperatures shoot up drastically, and the rock composition changes abruptly from a solid bulk of rock in the mantle to gooey iron sludge inside the core. To understand more about this boundary, scientists have looked at seismic waves coming from earthquakes. As these waves spread from the epicenter of the quake through the inside of our planet, they provide information about the Earth's innards. "Admittedly, to most people, seismic data is probably not that interesting to look at. It is a wiggly line that varies with time. But that wiggly line contains an amazing amount of information!" Hansen told Insider.