"Scientists Uncover Enormous Subterranean 'Ocean' Dwarfing Earth's Surface Seas"

Scientists have discovered a massive reservoir of water hidden 400 miles beneath the Earth's surface, contained within a blue rock called ringwoodite in the Earth's mantle. This reservoir is three times larger than all the oceans on the Earth's surface and was found using seismometers to measure earthquake waves. The discovery could help explain Earth's formation and the origin of its water, suggesting a whole-Earth water cycle and potentially reshaping our understanding of where Earth's water came from.