According to research, all the elements necessary for life were already present when the Earth was formed.

Latest research published in the journal Science Advances It challenges one of the most accepted scientific theories among planetary scientists: He said Earth received its volatile elements, especially those essential for life, when objects such as comets and asteroids carried them here from space.

According to the authors of the new study, these volatile elements necessary for life may have existed on our planet since its formation 4.5 billion years ago. The results obtained through first principles (ab initio) calculations challenge the propositions of the “Late Covering” theory, which refers to the addition of external material after the formation of the planetary core.

Because by definition volatile elements (carbon, hydrogen, and nitrogen) evaporate quickly in nature, the researchers worked with some materials called chalcogens, the old group 6A of the periodic table. These elements, such as sulfur, selenium and tellurium, are known to form compounds with oxygen..

How did scientists discover the origin of volatile substances on Earth?

To test their theory about the origin of volatiles on Earth, the authors worked with a computational technique known as first principles computation. This approach, derived directly from the fundamental laws of physics, It describes the behavior of isotopes, which are variants of the same chemical element that contain different numbers of neutrons.

Isotopes at each stage of Earth’s formation have different rates of radioactive decay due to different nuclear stabilities. So each isotopic form leaves its “signatures” that scientists can follow, sort of like fingerprints, after these primitive stages of terrestrial development.

Through first-principles calculations, the researchers calculated what isotope signatures were expected for various chalcogens depending on the period of Earth’s formation. These models, which included isotope predictions, were then compared to the planet’s actual chalcogen isotope measurements.

What did scientists conclude about the volatiles in Earth’s mantle?

The results showed: Although many volatile substances evaporated during Earth’s formation, when the earth was still extremely hot and bright, many of them remain here today. The findings suggest that many of today’s terrestrial volatiles likely came from early stages of planet formation.

The study concluded: “Sulfur, selenium, and tellurium isotope signatures of BSE [composição química média da Terra] “reveals that protoplanet differentiation plays a fundamental role in the formation of most volatile elements on Earth.” This means that late cover from space did not contribute to our volatile inventory as reported.

However, chalcogens as well as other volatile substances essential for life should also be examined in future research. Knowing the behavior of other elements, such as nitrogen, under extreme conditions is fundamental to understanding the evolution and habitability of terrestrial planets.

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