Underground 'oceans' beneath the Earth could reshape water cycle
Beneath the Earth's surface lies an expansive "ocean," which is three times larger than the Earth's surface oceans. However, it is not in liquid form.
Scientists have identified a gigantic ocean hidden hundreds of miles beneath the Earth's surface. Researchers have discovered that this underground water reservoir is three times larger than all the oceans on our planet combined. This finding could significantly alter our understanding of the Earth's water cycle.
Underground ocean in the transition zone
Researchers have long speculated about the existence of an ocean located between the upper and lower mantle, in what is known as the transition zone, at a depth of about 250 to 400 miles. Geophysicist Steve Jacobsen from Northwestern University and seismologist Brandon Schmandt from the University of New Mexico were the first to provide evidence for this structure in 2014.
This underground ocean extends beneath the United States at a depth of around 400 miles. Scientists identified this using seismographs deployed across the country, which detected seismic waves from over 500 earthquakes. These waves accelerated in the transition zone, suggesting the presence of a vast water reservoir.
Water trapped in minerals
The underground ocean is neither in liquid form nor ice; the water is trapped in the molecular structure of minerals within the Earth's mantle, specifically in a mineral called ringwoodite, a form of olivine. Ringwoodite contains between 2.5 to 3% water by weight.
This discovery may influence theories regarding the origin of water on Earth. It has long been thought that water arrived via asteroids or comets that collided with Earth billions of years ago. However, research by Jacobsen and Schmandt suggests that water may have originated from within the planet itself.
Underground oceans in the solar system
Similarly intriguing discoveries relate to Ceres, the dwarf planet between Mars and Jupiter. Data analysis from the Dawn probe indicates a potential ocean rich in organic materials beneath its surface. Studies imply that these substances might be endogenous and conducive to life forms. As a water-rich celestial body, Ceres represents an intriguing target for further research.
Mars, known for its past oceans, also harbors underground water reservoirs. The InSight mission revealed that the Red Planet has underground water that could cover the entire planet with an ocean 1 to 2 miles deep. This discovery sheds new light on the potential for life on Mars and its ancient climatic conditions, which might have been favorable for its development.
Similar indicators of subsurface oceans are found on Ariel, one of Uranus's moons. Observations from the Webb Telescope have revealed significant deposits of CO2, suggesting geological processes within the moon. This implies that Ariel might possess a hidden ocean supplying material to the surface through cracks in the ice crust, making it another exciting target for space exploration.
