Water on Earth may have resulted from an interaction between a hydrogen-rich atmosphere and the magma oceans of the planetary embryos that formed it, according to new work by Anat Shahar of Carnegie Science and Edward Young and Hilke Schlichting of the University of California, Los Angeles. The years of the formation of the world. Their findings, which may explain the origin of Earth’s characteristic features, are published in Nature.

For decades, much of what researchers knew about planet formation was based on our own solar system. While the formation of gas giants such as Jupiter and Saturn is hotly debated, Earth and other rocky planets are believed to have formed from the disk of dust and gas that surrounded our Sun in its youth.

As larger objects collided with each other, the baby planets that eventually formed Earth grew larger and hotter, melting into a vast ocean of magma due to the heat of the collisions and radioactive elements. Over time, as the planet cooled, the densest material sank inward, dividing Earth into three distinct layers: a metallic core and a rocky silicate mantle and crust.

However, the rapid development of exoplanet research over the past decade has created a new approach to modeling the embryonic state of the Earth.

“The discovery of exoplanets has given us much more insight into how often newly formed planets are surrounded by atmospheres rich in molecular hydrogen, H2, during their first few million years of growth,” Shahar said. “These hydrogen shells eventually disperse, but leave their traces on the composition of the young planet.”

Using this knowledge, researchers developed new models of Earth’s formation and evolution to see if the distinctive chemical properties of our home planet could be reproduced.

Using a newly developed model, Carnegie and UCLA researchers were able to show that in early Earth, interactions between an ocean of magma and the molecular hydrogen proto-atmosphere may have produced some of Earth’s signature features, such as abundant water. and the total oxidation state.

The researchers used mathematical modeling to probe the exchange of matter between the molecular hydrogen atmosphere and magma oceans, looking at 25 different compounds and 18 different types of reactions. A complete interpretation is sufficient.

The interaction between the igneous ocean and atmosphere on the simulated baby Earth drove large masses of hydrogen into the metallic core, oxidized the mantle and produced large quantities of water.

The researchers showed that even if all the rocky material that collided to form the growing planet were completely dry, these interactions between the molecular hydrogen atmosphere and the magma ocean would have created large volumes of water. They say other sources of water are possible, but they are not necessary to explain the current state of the Earth.

“This is only one possible explanation for the evolution of our planet, but one that establishes an important link between the history of Earth’s formation and the most common exoplanets, super-Earths and sub-planets orbiting distant stars. Neptunes,” Shahar said. has been finalized

This project was part of the interdisciplinary, multi-institutional AEThER project initiated and led by Shahar, which aims to explore the chemical composition of the most common planets in the Milky Way galaxy – super-Earths and sub-Neptunes – and develop a framework. detecting traces of life on distant worlds. This effort is designed to understand how the formation and evolution of these planets shaped their atmospheres. This could allow scientists to distinguish true biosignatures from non-biological atmospheric molecules, which can only be created by the presence of life.

“The increasingly powerful telescopes allow astronomers to understand the composition of exoplanet atmospheres in never-before-seen detail,” said Shahar. “AEThER’s work will complement its observations with experimental and modeling data, which we hope will lead to a seamless method for detecting signs of life on other worlds.”