Planets Could Create Their Own Water While Forming, Expanding Possibilities for Habitable Worlds

Water may not only arrive on planets on comets and asteroids but also occur naturally as worlds come of age, a new study suggests. In laboratory experiments that mimic the conditions of early planets, scientists brought together the intense heat and pressure where molten rock meets hydrogen gas. Those tests showed that liquid water could be created inside planets as they formed, providing new understanding about how Earth and other planets might come to possess life-supporting water. The results could revolutionise our understanding of the potential for habitable environments throughout the cosmos.

Planets Can Produce Their Own Water During Formation, Boosting Potential for Habitable Worlds

According to a report published in Nature on October 30, researchers led by Anat Shahar at the Carnegie Institution for Science compressed molten, iron-rich rock in a diamond anvil cell to nearly 600,000 times Earth's atmospheric pressure and heated it to more than 7,200°F. The experiments showed hydrogen reacts with iron oxides in molten rock, generating substantial water, without requiring delivery from comets or asteroids. This is in line with a theory that water should form naturally during planet formation.

The researchers concentrated on sub-Neptune analogues -- planets that are between Earth's and Neptune's size, which are the most abundant type in our galaxy. Those rocky, hydrogen-rich planets are useful to study early water formation — and could increase the number of potentially habitable worlds beyond our solar system.

Planetary formation, Shahar explains, naturally creates water, and by extension exoplanets that are rich in the substance may be even more common – and habitable – than previously thought. In the future, studies will be conducted of water's interaction with planetary materials to help astronomers characterise distant worlds with oceans, atmospheres, and possible life.