Meteorites could reveal the origin of some basic components of life like water

The bone volatile elements present on the planet are compounds that change from solid or liquid to vapor at relatively low temperatures. They include the six most common elements found in living organisms, as well as in the water. As such, the addition of these materials must have been important to the flourishing of life on Earth.

Researchers from Imperial College London found that about half of the volatile element zinc present on Earth came from asteroids originating from the outdoor solar system, the part beyond the asteroid belt that includes the planets Jupiter, Saturn and Uranus. This material is also expected to have contributed other important volatiles such as water.

Before that, researchers thought that most volatile substances on Earth came from asteroids that formed closer to the planet. Now, however, these discoveries reveal important clues about how Earth came to host the special conditions needed to sustain life.

Lead author of the paper just published in the journal Science, Mark Rehkämper from the Department of Earth Science and Engineering at Imperial College London, said: “Our data show that about half of Earth’s zinc inventory comes from material from the outer solar system, beyond Earth’s orbit. Jupiter. Based on current models of the early development of the solar system, this conclusion was completely unexpected.”

Previous research has suggested that the Earth formed almost exclusively from materials from the inner solar system, which the researchers inferred was the predominant source of volatile chemicals Of the earth. On the contrary, the new findings suggest that the outer solar system played a bigger role than previously thought.

“This contribution of materials from the outer solar system has played a vital role in establishing Earth’s inventory of volatile chemicals. It appears that without the contribution of materials from the outer solar system, Earth would have far fewer volatiles. than we know today, which would have made it a drier planet and potentially incapable of nurturing and supporting life.” Rehkamper.

As part of the study, the researchers examined 18 meteorites of various origins: eleven from the inner solar system, called non-carbonaceous meteorites, and seven from the outer solar system, called carbonaceous. For each meteorite, they measured the relative abundances of the five different forms, or isotopes, of zinc.

They then compared each isotopic fingerprint to samples from Earth to estimate the contribution of each of these materials to the planet’s zinc inventory. The results suggest that although the Earth was only incorporated around the ten% of its mass of carbonaceous bodies, this material provided about half of the zinc that the Earth contains today.

The researchers say that materials with high concentrations of zinc and other volatile components are also likely to be relatively abundant in water, giving clues to where this element originated on Earth.

The paper’s first author, Rayssa Martins, a doctoral candidate in Imperial’s Department of Earth Science and Engineering, said: “We have known for a long time that carbonaceous materials have been added to the Earth, but our findings suggest that these materials played a key role in the establishment of volatile elements, some of which are essential for the flourishing of life.

Next, the researchers will analyze rocks from Mars, which held water 4.1 to 3 billion years ago before drying up, and from the Moon. “The widely held theory is that the Moon formed when a huge asteroid crashed into an embryonic Earth a few years ago. 4.5 billion years old. Analysis of zinc isotopes in moon rocks will help us test this hypothesis and determine whether the colliding asteroid played an important role in delivering volatile substances, including water, to Earth.” concluded Rehkämper.

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