Earth May Have a Massive Sixth Ocean Underground, Study Shows

by Suzanne Halliburton

Cue the cool, mystical music. Scientists believe Earth has a sixth ocean, but it’s so far below the planet’s surface that no one ever will see it.

And to think, a diamond revealed the details.

Depending on how old you are, you learned in school about the four oceans on Earth. They are the Atlantic, Pacific, Indian and Arctic. The  International Hydrographic Organization recognized a fifth ocean back in 2000.

So what about the sixth ocean? If we can’t see it, where exactly is it? It’s possibly 400 miles deep into the Earth’s core. Scientists believe that this sixth ocean exists because of a diamond found in Botswana. Trapped inside the gem were imperfections that only could be caused by water and other minerals found deep inside the planet.

Scientists from the United States, Italy and Germany recently published the results of their research in the journal Nature Geoscience.

Now, consider that the deepest hole ever bored into the Earth’s surface goes down only about seven miles. It kind of blows the mind that this sixth ocean could be another 93 miles down.

Sixth Ocean Likely Won’t Look Like Other Five

Nature GeoScience points out that Earth sometimes is described as a referred to as water planet. That’s because more than 70 percent of the surface is water. Ocean water can be cycled by hydrated minerals deep into the Earth. And then volcanic activity can push the water back towards the surface. Scientists call this the deep water cycle. However, it’s difficult to study because no one has figured out a way to go that deep into the surface.

The researchers studied a gem-quality diamond discovered in the Karowe mine in Botswana. This mine is known for producing huge stones of more than 10.8 carats, like the 1,758-carat Sewelô, the 1,109 Lesedi La Rona and the 813 Constellation.

The stone that researchers studied showed evidence of ringwoodite and other hydrous minerals. Scientists determined it formed in a hydrated region of the Earth’s mantle. They reached this conclusion because two of the minerals tend to occur at depths of 400 miles. Plus, this is also the area where seismic waves start changing speeds.

And thus, the sixth ocean, although it probably won’t look like the other five.