[ad_1]
Researchers have reported that salt water just below the surface of Mars may contain enough oxygen to support the type of microbial life that has emerged and flourished on Earth billions of years ago. # 39; years.
In some places, the amount of oxygen available could even keep alive a primitive multicellular animal like a sponge, they reported in the newspaper
Geoscience of Nature
"We found that brines" – water containing high concentrations of salt – "on Mars may contain enough oxygen to allow microbes to breathe," said lead author Vlada Stamenkovic, a physicist specialist in theory at the Jet Propulsion Laboratory in California. [19659002] "This completely revolutionizes our understanding of the potential of life on Mars, today and in the past," he told AFP.
Until now, it was badumed that traces of oxygen on Mars were insufficient to support even microbial life.
"We never thought that oxygen could play a role in life on Mars because of its scarcity in the atmosphere, about 0.14%," Stamenkovic said.
In comparison, the gas that gives life constitutes 21% of the air we breathe.
On Earth, life forms evolve along with photosynthesis, which transforms CO2 into O2. Gas played a vital role in the emergence of a complex, remarkable life after the so-called great oxygenation event of 2.35 billion years ago.
But our planet is also home to microbes – at the bottom of the ocean, in boiling hot springs – that persist in oxygen-deprived environments.
"That's why, whenever we think of life on Mars, we are studying the potential for anaerobic life," Stamenkovic. oxides, which are chemical compounds that can only be produced with a lot of oxygen.
Curiosity, with the orbiter of Mars, has also established the presence of brine deposits, with notable variations in the elements that they contain.
The contents allow the water to remain liquid – a necessary condition for the dissolution of oxygen – at much lower temperatures, making the brine a place conducive to microbes.
By region, season and time, climate Temperatures on the red planet can range from minus 195 to 20 degrees C.
Researchers have come up with a first model describing how 39, oxygen dissolves in salt water at temperatures below the freezing point. A second model estimated climate change on Mars over the last 20 million years and 10 million years to come.
Overall, calculations have shown which areas of the red planet are most likely to produce brine – based oxygen. could help determine the location of future probes. "The study indicates that oxygen concentrations [on Mars] are several orders of magnitude – several hundred times -" more than necessary for aerobic microbes or breathing oxygen ". AFP
• The new study began with the discovery by the robot-emitter Curiosity NASA of manganese oxides, chemical compounds that can not be products that with a lot of oxygen.
• Curiosity, with Martian orbits, also established the presence of brine deposits, with notable variations in the elements they contain.
Place for microbes.
[ad_2]
Source link
