Deep within Earth, at a depth of 700km, scientists have discovered evidence of a giant underground ocean deep inside the planet's crust. Surprisingly, this hidden ocean could hold three times more water than all the oceans on the surface.
For many years, researchers have debated the origin of water on Earth: Water brought by icebrones to Earth or water appearing deep inside the planet? A groundbreaking discovery is leaning towards a second hypothesis.
Scientists study the mineral ringwoodite - a green stone found in the Earth's crust - and have discovered that the stone can hold a huge amount of water inside the crystal structure.
Located about 700km below ground, this hidden water area forms a structure called the "mantle ocean", a giant ocean that challenges everything we know about the hydrological history of the Earth.
Many researchers believe that this discovery could completely reshape the theories of how the ocean formed. Instead of being brought in from outside the cosmic space, Earth's water may have been slowly leaking out from within, a concept that disrupts traditional thinking about the origin of water on Earth.
To explore the underwater ocean, geologists deployed more than 2,000 seismometers across the United States and analyzed seismic waves from more than 500 earthquakes.
When transmitted through wet rocks, the earthquake waves slow down. That small delay, measured with extreme accuracy, allows scientists to pinpoint the giant water bags trapped deep under the Earth's crust.
That is the most compelling evidence we have that the Earths water comes from within, explains Steven Jacobsen, a researcher at Northwestern University.
Jacobsen pointed out that this giant underwater ocean could also help explain why sea levels have remained relatively stable for millions of years. Without this underground buffer layer, the Earth could have a very different landscape, with vast waters and only the highest mountains rising above sea level.
The discovery of a giant ocean about 700km underground not only re-writes the past, but can also reshape the way people think about the future. If a huge amount of water is deep in the Earth's crust, the Earth's water cycle is likely to be much more complex than surface evaporation and rainfall.
After the discovery of this giant ocean, the next phase of the study will include collecting seismic data from around the world to determine whether the huge amount of water hidden inside the Earth's crust is a global phenomenon. If true, scientists may have to redefine one of the basic processes that determine the shape of the planet.
