Massive ocean discovered beneath our feet that has three times more water than Earth’s surface

The ocean covers more than 70 percent of the surface of the Earth, but it's still not the biggest body of water our planet has to offer.

Scientists might have thought it was for a long time, but that all changed in 2014.

That was when a team of scientists from Northwestern University in Illinois discovered a new ocean; one hidden way beneath our feet.

The discovery came after the team used seismometers to measure the waves being generated by earthquakes across the US.

The newly discovered ocean is bigger than those on the surface (Getty Stock Photo)

When analysing the results, the scientists realized the waves weren't limited to the Earth's surface, but were moving throughout the planet's core.

They then set about measuring the speed and depth of those waves to figure out what kind of rocks were holding the water.

The research revealed the newly-discovered ocean, hidden a whopping 400 miles underground, is contained inside a blue rock known as 'ringwoodite', which is in the Earth's mantel.

The water is not held as a liquid, solid, or gas, but instead as a fourth molecular structure of water contained inside the mantle rock.

Geophysicist Steve Jacobsen, who was part of the discovery, explained: "The ringwoodite is like a sponge, soaking up water, there is something very special about the crystal structure of ringwoodite that allows it to attract hydrogen and trap water.

The underground ocean could offer insight into where the Earth's water came from (Getty Stock Photo)

"This mineral can contain a lot of water under conditions of the deep mantle."

The substance can contain up to 1.5 percent water, and if the ringwoodite under the surface has just 1 percent water in its molecular build-up, it would mean that it holds three times more water than all of the oceans on the Earth's surface.

It's hard to imagine, right? But studies of the water could prove vital in helping scientists determine how Earth was formed.

In contrast to the idea that the Earth's water came from asteroids and comets, the discovery could further the theory that the Earth's water 'came from within'.

Jacobsen explained at the time: "I think we are finally seeing evidence for a whole-Earth water cycle, which may help explain the vast amount of liquid water on the surface of our habitable planet.

"Scientists have been looking for this missing deep water for decades."

Following the discovery of the ocean, Jacobsen and his team in Illinois turned their attention to figuring out whether or not this layer wraps around the entire planet Earth.