Arizona, Katra.com- Saturn’s moon may be operating an unknown methane production process in the ocean hidden beneath the ice sheet of Enceladus. According to a new study published in Natural astronomy By scientists University of Arizona And University of Paris Sciences & Letters. Science, 06/07.
The giant fountain that erupts from Enceladus has long fascinated scientists and the general public with research and speculation about a vast ocean believed to be sandblasted between Enceladus’ rock center and its iceberg. Flying through the bubble and modeling its chemical makeup, the Cassini spacecraft detected relatively high concentrations of some molecules compared to the hydro temperatures at the Earth’s ocean floor, particularly dihydrogen, methane and carbon dioxide. The amount of methane found in the giant jet of water is unexpected.
“We wanted to know: Can earth-like microbes ‘eat’ hydrogen and produce methane to explain the surprising levels of methane casein?” Regis Ferrier, a professor of ecology and evolutionary biology at the University of Arizona, is one of the study’s two leading teachers. “The search for such microorganisms known as methanogens in the oceans of Enceladus will require a very challenging deep diving mission that has not been seen for decades.”
Ferrier and his team took a different and easier path: different processes, including biological methanogenesis, developed mathematical models to calculate the probability that Cassini could explain the data.
The authors used a new mathematical model that combines geochemistry and microbiology to analyze water jet data from Cassini and to model possible processes that better explain observations. Cassini concluded that the data correspond to processes involving micro hydro thermal vents or to life forms, but they are different from phenomena occurring on Earth.
On Earth, water heating activity occurs when cold seawater travels to the ocean floor, passes through a rock below, and approaches a heat source such as the magma chamber, before being spit back into the water through hydrophores. On Earth, methane can be produced by the thermal action of water, but at a slower rate. Most of the production is caused by microorganisms that utilize chemical imbalances through the energy of hydrogen produced as hydro heat, and are produced from carbon dioxide in a process called methane methanogenesis.
The team observed that Enceladus erupted as the end result of many chemical and physical processes inside the Moon. First, the researchers assessed that the hydrothermal production of hydrogen was very relevant to Cassini’s observations, and that this production could provide enough “food” to sustain populations of hydrogenotropic methanogens such as Earth. To do so, they developed a model for the demographic dynamics of a hypothetical hydrogenotropic methanogen whose heat and energy locations are modeled according to known strains from Earth.
The authors then directed the model to see if certain chemical conditions, such as the hydrogen concentration and temperature in the hydrothermal fluid, would provide the right environment for these microbes to grow. They also observed the effects of imaginary microbial populations on their environment – for example, at the rate of release of dihydrogen and methane into that jet of water.
“In short, Cassini’s observations were not only able to assess whether they fit into the living environment, but also to make quantitative predictions about the expected observations if methanogenesis occurs in the oceans of Enceladus,” Ferrier explains.
The results show that even the highest estimates of aziotic methane production based on known hydroelectric chemistry – or even unaided biological methane production – are not sufficient to explain the methane concentrations measured in Enceladus water jets. However, the addition of biological methanogenesis to the mixture may produce methane that is compatible with Cassini’s observations.
“We have not decided that there is life in the oceans of Enceladus,” Ferrier said. “Instead, we wanted to understand how it is possible that Enceladus’ hydrothermal vents are inhabited by microorganisms such as Earth. According to our model, the Cassini data could tell us,” he said.
“Further biological methanogenesis appears to be consistent with the data. In other words, we cannot deny that the ‘life hypothesis’ is very unlikely. To reject the life hypothesis, we need additional data from future trips,” he said.
The authors hope that their paper will provide guidelines for research aimed at better understanding Cassini’s observations and encouraging research to clarify azionic processes that can produce enough methane to compute Cassini data.
For example, methane may come from the chemical decomposition of primitive organic matter that may be at the center of encephalitis, and they may be partially converted to hydrogen, methane, and carbon dioxide by hydrothermal processes. This hypothesis makes a lot of sense if we know that Enceladus was formed by adding organic-rich substances provided by the comet, Ferrier explained.
“It comes down to how much we believe in starting different hypotheses,” he said. “For example, if the probability of life on Enceladus is considered very low, such alternative agiotic mechanisms will become very high, even if they are very alien compared to what we know on Earth.”
According to the authors, the most promising improvement in this study lies in its approach, as it is not limited to specific systems such as the inner oceans of icy moons and will be available in the coming decades when dealing with chemical data from planets outside the solar system.
The full list of authors and funding information can be found in the paper, “Poisson’s analysis of Enceladus’ Bloom data to evaluate methanogenesis,“Inside Natural astronomy July 7 Magazine.
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