Curiosity finds biologically probable carbon in Martian rocks

Included in three scenarios including space dust… Additional data needed to confirm

(Seoul = Yonhap News) Reporter Nam-seok Eom = It was announced that rock samples collected and analyzed by the US Mars rover Curiosity contained carbon that may be related to biological processes.

A research team led by Dr. Christopher House, a professor of earth science at Pennsylvania State University (PSU), USA, analyzed the carbon stable isotope ratio of 24 rock powder samples collected by the Curiosity spacecraft from the Gale Crater, where the ancient rock layers of Mars were exposed. published in the Bulletin (PNAS).

According to the Jet Propulsion Laboratory (JPL) and PSU, which operate the Curiosity, Curiosity heats a powder sample obtained by drilling a hole in the rock to 850 degrees and analyzes the emitted gas with a ‘tunable wavelength laser spectrometer’ (TLS) to determine carbon dioxide. The ratio of -12 to carbon-13 was analyzed.

The research team found samples with extremely low carbon-13 ratios from data transmitted by Curiosity on-site analysis, and suggested three scenarios in which this type of carbon could be created, including biological processes.

“These samples are extremely carbon-13-depleted, similar to those from Australian sediments about 2.7 billion years ago,” House said. “It is caused by the biological activity of absorbing methane produced by other microorganisms, but we cannot assert that it is the case on Mars, which may have been formed from other materials and processes than Earth,” he said.

The research team first heard the possibility that it was formed by accumulation of cosmic dust.

The solar system passes through the molecular clouds of our galaxy every hundreds of millions of years, and these clouds cool the temperature of Mars, which still has water, to form glaciers, and the dust accumulated on the ice later melts and forms a layer containing the same carbon as the sample. that it may have formed.

Although the evidence for glaciers at Gale Crater is limited, the team said, “It makes a lot of sense and further research is needed.”

In addition, it was suggested that there is a possibility that ultraviolet rays caused a photochemical reaction with carbon dioxide in the atmosphere and accumulated organic compounds containing carbon on the surface, but additional experiments were needed to confirm this.

Regarding the biological potential, the research team said that ancient Mars released a large amount of methane from the underground, which could have been consumed by microorganisms on the surface or reacted with ultraviolet rays and accumulated directly on the surface.

However, since there is no evidence of surface microbe activity on Mars, it is more likely that the methane emitted into the atmosphere reacts with ultraviolet light and turns into larger and more complex molecules that accumulate on the surface.

“All three possibilities are rare carbon cycles that are unlikely to occur on Earth today,” House said. “We need more data to know which one is the correct scenario.”

eomns@yna.co.kr

<저작권자(c) 연합뉴스,
Unauthorized reproduction-redistribution prohibited>
2022/01/18 16:21 Send