Scientists have traced the origin of volatile compounds essential for the emergence of life on Earth.

The origin of the first building blocks of life on Earth remains a topic of intense debate. Recently, scientists discovered isotopic anomalies of zinc in meteorites, suggesting a source from which they originated. In a new study, cosmochemists from the UK analyzed a large number of celestial bodies and determined the regions of the Solar System from which volatile components arrived on Earth.

2024-10-13 07:30:25https://naked-science.ru/article/chemistry/uchenye-prosledili-istoch

Substances that condense at relatively low temperatures (below 1100 Kelvin) are referred to as volatile. They include six of the most common elements found in living organisms and water. Their presence on Earth was a condition for the emergence of life.

According to a hypothesis, volatile elements for terrestrial planets were delivered by carbonaceous chondrite meteorites. Recent studies have shown that both carbonaceous and non-carbonaceous chondrites were significant sources of potassium and zinc (considered a moderately volatile element). The contribution of each type of source remains unknown. Scientists led by Raissa Martin from Imperial College London have taken on the task of uncovering this.

The research, published in the journal Science Advances, presents data on the zinc isotope content in meteorites formed from different planetesimals. These primitive bodies were created through the accretion of primordial material in the Solar System. The Earth formed from these planetesimals.

The first batch of planetesimals underwent intense melting due to radioactive irradiation, resulting in the loss of volatile components. Bodies formed later did not melt, thus preserving primitive material. These differences are recorded in the ratios of isotopes, which serve as unique chemical markers. These are very small anomalies known as mass-independent (because their fractionation did not depend on the mass of the isotopes).

Data on mass-independent zinc anomalies in meteorites composed of materials from various planetesimals were used to model the first tens of millions of years of Earth's formation.

It was found that only ten percent of zinc originates from the melted planetesimals, even though Earth is composed of them to the extent of 70 percent. The remaining zinc comes from primitive material that avoided melting. This indicates that it is the source of the majority of volatile elements on Earth.

For the search for life on other planets in the Solar System and beyond, it is important to trace the fate of chemical elements over millions and even billions of years of evolution. Researchers now have another marker that allows them to assess the habitability of other worlds.