Overview

As it turns out, Earth has a sixth massive ocean but you can’t see it. The ocean is located in the transition zone, between the upper and lower mantle, at a depth of 410 to 660 kilometers (255 to 410 miles) into the Earth’s interior, and that’s only one of the interesting things about it.

The science and other stuff to know

After examining a very rare diamond from Botswana, which, based on its chemical composition, was formed at a depth of 660 kilometers (410 miles) in extremely watery conditions, a team of researchers from Goethe University Frankfurt came to the conclusion that the Earth’s mantle has an ocean. The finding suggests that there is a lot of water trapped tightly within the rocks in this very deep region of the Earth.

But how did the researchers learn all that from looking at that diamond alone? The diamond had “inclusions”, or pockets, of ringwoodite, an element that only forms under high levels of pressure and temperatures in the Earth’s mantle, but can hold water quite well, according to an international study published in Nature Geoscience.

While the transition zone is likely a dark slurry of sediment and hydrous rock with near-inconceivable pressures, it can hold large volumes of water. In fact, according to the study, it may contain up to six times the amount of water present in all of the Earth’s oceans combined! “These sediments can hold large quantities of water and CO2,” said Frank Brenker, a researcher at the Institute for Geosciences at Goethe University in Frankfurt, in a statement.

So what?

Over the past few centuries, we’ve learned much about Earth, which has only deepened our fascination with it. Aside from the fact that it’s the only planet known (so far) to support life, it’s awe-inspiring and scientists are finding new, interesting discoveries every year such as the latest find about the ocean in the Earth’s interior.

With all the advanced technology, just imagine what amazing discoveries we can find beyond our planet — in outer space. For instance, scientists have recently discovered two new “super-Earth” planets just 100 light-years away, and one may support life.

What’s next?

Scientists have long speculated that water is trapped in a rocky layer of the Earth’s mantle. The Goethe University Frankfurt study offers more insights and affirms the 2014 discovery by researchers from Northwestern University and the University of New Mexico who reported evidence of a potential ocean deep toward the Earth’s core.