Jules Verne was right, scientists have just discovered an ocean at the Earth’s core, challenging our understanding of the universe

A hidden world of water lurks deep beneath our feet, rewriting geologists’ playbook on Earth’s composition. Recent finds confirm that the mantle’s transition zone could harbour an ocean’s worth of water—echoes of Jules Verne’s wild imagination.

Two discoveries ten years apart

Imagine stumbling upon evidence of a hidden sea while digging for diamonds. That’s exactly what happened in 2009 when Dr Graham Pearson’s team at the University of Alberta unearthed a fragment of rock containing ringwoodite from between 410 and 660 km beneath Brazil’s surface¹.

Did you know? Ringwoodite was first identified in a meteorite in 1969, long before any terrestrial sample was found.

Fast forward to a later discovery, and a second ringwoodite inclusion was recovered from a kimberlite-hosted diamond in Botswana—analysed by researchers at the Gemological Institute of America—confirming the mantle’s hydrous nature².

The stone found in 2009 by Graham Pearson and his team.
An ocean beneath our feet, but not as you imagine

Before these breakthroughs, most of us pictured Earth’s inner water as molten or liquid. In reality, the water exists as hydroxyl ions (OH⁻) woven into the crystal structures of high-pressure minerals. Geologists now estimate that the mantle transition zone could hold as much water as all the world’s oceans combined³.

This isn’t just academic curiosity. Dr Pearson suggests that this vast reservoir may drive the deep water cycle, influencing everything from volcanic activity to plate tectonics⁴.

I’ll never forget hiking on a desert trail and spotting a small spring bubbling through dry earth—it was a tiny reminder that water often hides where we least expect it. These findings take that lesson to a planetary scale: the most critical oceans may be concealed far beneath our feet, shaping the very dynamics of Earth’s interior.

As researchers continue to probe these mysteries, one thing is clear: Jules Verne’s imaginative journey to Earth’s core may have been more fact than fiction. And with every new discovery, our understanding of the universe grows just a little deeper.

Footnotes

D. G. Pearson, F. E. Brenker, F. Nestola, J. McNeill & L. Nasdala. “Hydrous mantle transition zone indicated by ringwoodite included within diamond.” Nature. 2014;507(7491):221–224. https://doi.org/10.1038/nature13080
Wikipedia contributors. “Ringwoodite.” Wikipedia. https://en.wikipedia.org/wiki/Ringwoodite
Wikipedia contributors. “Transition zone (Earth).” Wikipedia. https://en.wikipedia.org/wiki/Transition_zone_(Earth)
Wikipedia contributors. “Deep water cycle.” Wikipedia. https://en.wikipedia.org/wiki/Deep_water_cycle

Jules Verne was right, scientists have just discovered an ocean at the Earth’s core, challenging our understanding of the universe

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