Ancient Mars may have had oceans because it had a hydrogen-rich atmosphere | sorae space gate

From SETI InstitutePelivan cafeResearch team led byAncient Mars had an atmosphere rich in hydrogenAnnounce your search results. According to the research team, the atmospheric pressure on Mars at that time was much higher than it is today.The greenhouse effect may have kept the oceans warm (and possibly hot)It seems there

Possibility that the greenhouse effect of a hydrogen-rich atmosphere entrapped the Martian ocean

Mars todayIt has a thin atmosphere consisting mainly of carbon dioxide (atmospheric pressure is about 6/1000 of that of the Earth),cold and dry planetHe.However, on the surface of ancient MarsEnough water to form an oceanIt is believed that there was a time when an asteroid existed in a liquid state, and this life may have been born.

“It’s a contradiction,” said an Arizona State University professor who took part in the study.Mr. Steve Deschhe is. Desch says a number of observations have shown that liquid water was present on the early surface of Mars, even though water on Mars froze even today when the sun is 30 percent brighter than it was in antiquity. It refers to the points you gave If there really was an ocean, Mars at that time would have been well equipped to hold liquid water on its surface.

Therefore, the research team built a new model for the evolution of the Martian atmosphere. The model relates the formation of the first oceans and atmosphere to high temperatures when the surface of Mars melted and was covered with a rocky ocean. As a result of analysis using the new model, the main gas generated is from lava.A mixture of molecular hydrogen and water vaporIt proved possible.

The team’s model showed that in the atmosphere of early Mars, water vapor behaved the same as in Earth’s atmosphere today.Water vapor condenses in the lower atmosphere to form cloudsThe upper atmosphere dried up. On the other hand, hydrogen does not condense at any altitude and is a major component of the dry and vapor-poor atmosphere. It turns out that hydrogen eventually escapes from the upper atmosphere into outer space and is lost from the Martian atmosphere.

The points, along with water vapor, may have formed the atmosphere of early Mars.The presence of hydrogenhe is. According to Pahlifan, hydrogen molecules are in a dense environmentstrong greenhouse gasesIt is known to be models suggest that the atmospheric pressure of early Mars was more than 1,000 times higher than today, and that it would have been a long time before the atmosphere lost its warming-promoting hydrogen.Possibility of a stable warm ocean for millions of yearsIt is said that there is

The SETI Institute, which promotes the search for intelligent extraterrestrial life,Pay attention to this result from the point of view of lifea job. In the famous Urey-Miller experiment conducted in the mid-20th century, in a hydrogen-rich (reducing) atmosphere, compared to a hydrogen-poor (oxidizing) atmosphere, it was found that the substances that give birth to life can be easily produced. .Models suggest that early Mars may have been as promising a place for the origin of life as early EarthThe research team hopes that there may be traces that can be detected by current Mars rovers.

The research team concluded that the average temperature on Mars would be from 290 to 560 K (about 17 to 287 °C) due to the greenhouse effect of the hydrogen atmosphere from 1 to 100 bar (1,000 to 100,000 hectopascals) coexisting with it. It appears that there is a possibility that The sea water temperature at that time is very high.

■ A natural explanation for the hydrogen isotope ratio on Mars

【▲ Selfie image taken by NASA’s Curiosity spacecraft. Released March 30, 2021 (Credit: NASA/JPL-Caltech/MSSS)】

The research team’s work has also provided new explanations for water on Mars.

Forms a water molecule with oxygenhydrogenthe majority“one proton”It has a nucleus, but it is found in nature in very small quantitiesDeuterium(a stable isotope of hydrogen) is“One proton and one neutron”It has a core made of water found in the Martian meteorite that flew to EarthD/H . ratio(deuterium to hydrogen ratio), the value is similar to the D/H ratio of seawater on Earth. Martian meteorites consist primarily of igneous rocks derived from the inner mantle of Mars, and the water in them was incorporated during the formation of Mars.Mars and Earth are formed with the same D/H ratio and the same origin as waterIt is said that he thinks it is.

However, NASA’s rover on Mars“Curiosity of”3 billion years ago usingThe D / H ratio of clay formed on Marswhen I checkedThree times larger than the Earth’s oceansIt turns out that in other words, from the birth of Mars to the formation of clay, the water on the surface of Mars had a high content of deuterium for a reason. The ratio of D / H increases with the increase of deuterium,It also increases with decreasing amount of hydrogen.。

Water on Mars is thought to have been lost due to the decomposition of ultraviolet radiation in the upper atmosphere or its transport into the interior of Mars. Also, as mentioned above, the model created by the research team lost hydrogen from the upper atmosphere of Mars. Deuterium is slightly heavier than hydrogen, so it is lost from the atmosphere at a slower rate. Assuming that the atmosphere of early Mars was rich in hydrogen, this resulted inWater on Mars has a D/H ratio 2-3 times higher than the water trapped inside.The research team’s model is said to show this, and it aligns with the results of the analysis by Curiosity.

“This important finding that water vapor condenses and remains on early Mars, while hydrogen is lost without condensation,” said Pahlifan, “can be directly linked to Curiosity’s measurements.”The first model that naturally reproduces traditional noteswhich gives us confidence that the evolutionary scenario we describe is consistent with the first Martian events.”

Connection:NASA’s Insight landing site on Mars may not contain water ice as deep as 300 meters

source

• Image Credit: ESO/M. Kornmeiser/N. Risinger (skysurvey.org), NASA/JPL-Caltech/MSSS
• SETI Institute New evidence about Mars’ early atmosphere points to a wet planet capable of supporting life
• ASU The first hydrogen-rich atmosphere of Mars was inferred from the mud on its surface
• Pahlivan et al. The primordial origin of deuterium enrichment in the Martian hydrosphere (arXiv)

Text / Matsumura Takehiro