Earth's Hidden Ocean: Discovered 700 km below, challenges water cycle theories, redefining Earth's geology. 

Hydrological Rewrite: Source of water questioned; seismic waves decode secrets of internal reservoirs. 

Seismic Sleuths: 2000 seismographs unveil whispers of dampened rock, leading to hidden ocean's location. 

Unveiling Earth's Past: Jacobsen's research offers insight into mantle water, shaping early planetary formation. 

Planetary Exploration: Inspired by discovery, scientists globally seek to unveil mantle water's mysteries.