Imagination of the formation of a reducing atmosphere in the early Earth’s magma ocean (Image from Yonsei University, AI made via canva.com)
Professor Lee Yong-jae of the Department of Earth System Science at Yonsei University (Leader Research Project High-Pressure Mineral Physics and Chemistry Research Group) research team discovered that during the moon-forming impact that occurred on the early Earth, water and carbon dioxide contained in the magma ocean were converted into iron, which is the main component of the impactor’s core. Research results have been published showing that a reducing atmosphere can be temporarily formed, which is an essential environment for the natural synthesis of organic matter, which is a prerequisite for the hypothesis of the origin of life on Earth.
This research was conducted jointly with the 4th generation linear accelerator (PAL-XFEL) research team at Pohang Accelerator Research Institute (Director Kang Heung-sik) and the German PETRA III accelerator research team.
It is estimated that the great impact that formed the Moon about 4.5 billion years ago temporarily turned the entire Earth into a magma ocean and completely changed the existing atmosphere. Meanwhile, the Earth’s current atmosphere is known to have existed in an oxidized state since about 4 billion years ago, in the early Archean Era, under the influence of gas components emitted from the upper mantle in the past. Therefore, the existence of a reducing atmosphere must be traced back to the time of the early Earth, about 4 billion years ago.
In the scientific community, discussions continue about the evolution of the Earth after the great impact that formed the Moon, and recent studies have shown that through computer simulations, the iron core of the planetesimal that collided with the Earth is expected to have flowed into the Earth and reacted significantly with the material in the magma ocean. .
Accordingly, Professor Lee Yong-jae’s research team used an ‘X-ray free electron laser’, known as the most powerful X-ray source in existence, to instantaneously apply several megajoules (MJ) of energy to iron, thereby creating a magma ocean environment caused by a major collision. I copied it and observed it.
Researcher Jinhyeok Choi, the first author of the paper, is preparing for an X-ray free electron laser experiment. Source: Yonsei University
A small high-pressure generator, the Diamond-anvil Cell, was used to experimentally simulate the reaction between the nucleus of a planetoid and volatile substances such as water and carbon dioxide in the magma ocean caused by the large moon-forming impact. Using this, a pressure equivalent to about 50,000 to 100,000 times the atmospheric pressure is applied to a mixed sample of iron, water, and iron and carbon dioxide, and then a short pulse X-ray free electron laser generated by a 4th generation linear accelerator is used. An ultra-high temperature and ultra-high pressure environment was instantly formed.
As a result of observing the reaction and the process through a continuous It was confirmed that FeO) was produced. At this time, when the initial pressure was more than 10 GPa (approximately 300 km deep in the magma sea), the hydrogen captured within the iron structure remained in the form of iron cargo (FeHx) even after temperature-pressure restoration.
In the reaction between iron and carbon dioxide, iron and oxygen, which make up carbon dioxide, combine to produce iron oxide, as in the reaction with water, and carbon monoxide (CO) gas is released.
This reaction pattern forms a reducing atmosphere by hydrogen and carbon monoxide released by the great impact, iron composes the Earth’s mantle in the form of iron oxide, and iron cargos made stably in deeper areas move to the center and contain lighter elements. This suggests that a nucleus was formed.
Professor Lee Yong-jae of Yonsei University said, “This study is the result of the first experimental observation of the reaction between iron and volatile substances that occurred in a major impact environment, and directly implements the formation process of the reducing atmosphere, which is the key to the birth of life on the early Earth, in a laboratory environment.” He explained the significance of this study by saying, “Starting with a great collision simulation experiment using an
The research results were published in ‘Science Advances’ on December 15 (local time).
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