No asteroid impacts needed: Newborn Earth made its own water, study suggests

Our blue planet: Three-quarters of Earth's surface is covered by water.

Contrary to a popular theory that icy comets or asteroids delivered water to a dry newborn Earth, the planet itself may have produced its earliest water supply, a new study suggests.

This water would have stemmed from chemical interactions between an atmosphere rich in hydrogen, which researchers think enveloped the young Earth, and massive oceans of magma on the planet's surface.