Given the seeming paucity of moisture in the leftover remains of Earth's building blocks, planetary scientists have long assumed our planet's water supply came after it formed in a rain of hydrogen-soaked rocks and comets.

Researchers say they discovered evidence that early Earth was home to more hydrogen than previously thought, calling into question widely held beliefs about the origins of water and the planet’s evolution.

Scientists have long questioned whether an early Earth could have contained the appropriate hydrogen and oxygen on its own to create the water on our planet.