Scientists have discovered that Earth's core may contain as much as 45 oceans' worth of hydrogen, which could make it the planet's largest hydrogen reservoir. This finding suggests that Earth acquired most of its water during its formation, rather than later through comet impacts. The core, mostly made of iron and nickel, powers Earth's protective magnetic field. Hydrogen's presence in the core is significant because it can only enter the core-forming metallic liquid during Earth's main growth phases. This discovery is crucial for understanding planetary formation and the evolution of life on Earth. However, the amount of core hydrogen could be much higher than the new estimate suggests, and more work is required to confirm and fine-tune this estimate.
