Illustration : paysage martien sous un climat plus chaud et humide, comme c'était le cas il y a plus de 3,5 milliards d'années. La vie s'était-elle installée à sa surface à cette période ? © dottedyeti, Adobe Stock

The basic ingredients necessary for life were present on Mars

#basic #ingredients #life #present #Mars

Since 2012, the homeless Curiosity is conducting research on the surface of Mars with the goal of better constraining the evolution of the climate of the red planet and the presence of water liquid in its past, but also to determine whether or not Mars was capable of supporting life.

If we now know that many lakes and rivers have shaped the Martian landscape and that their heated it was a propitious day for life, no direct biological trace has yet been found. It does not matter, scientists continue to search, in particular focusing on the presence of the elemental chemical bricks necessary for the Figurative sense: sudden appearance of an idea, of a social, economic, political fact.
The term emergence is used in many fields.
Out…” data-image=”” data-url=” https ://” data-more=”Read more”>appearance of the life.

An amount of organic carbon comparable to certain terrestrial regions

In 2014, Curiosity thus carried out a series of experiments to measure the fraction of Generalities
Symbol: CAtomic number: 6Electrons per energy level: 2.4Atomic mass: 12,011 uMost stable isotopes: 12C stable with six…” data-image=” images/ midioriginal/ 2/1/9/2198868bcb_69707_carbone.jpg” data-url=”” data-more=”Read more”>Coal total organic matter contained in Martian rocks. After eight years of data analysis, the results are finally available in the journal. PNAS and reveal that Martian rocks are relatively rich in organic carbon, which is one of the key components for the start of This is a process that has the particularity of completely preserving matter. Putting it together, the…” data-image=”” data- url=”https: / /” data-more=”Read more”>chemical reactions prebiotics and potentially building of biological molecules.

It has been some time since scientists found traces of organic carbon in the Red planet. But the evaluation of its available amount is an important parameter that determines the development potential of life. And the results are quite surprising, as they show that Martian rocks contain a significant fraction of organic carbon, comparable to certain terrestrial regions. It is true that the values ​​are quite similar to those of harsh environments depleted in organic carbon (for the repository terrestrial), as Atacama desert, but these are encouraging results as far as Mars is concerned. Because it shows that carbon was available in sufficient quantity for construction (hypothetical) organic moleculeswhich are the basis of all forms of life known to date.

Water, carbon, energy sources… all the ingredients of life together

Total organic carbon is defined as the number of bonded carbon atoms in organic molecules (usually composed of carbon atoms).
Symbol: H Atomic Number:…” data-image=”” data-url =”” data-more=”Read more”>hydrogenGeneral
Symbol: ON Atomic number: 8 electrons per energy level: 2.6 Atomic mass: 15,999 u Most stable isotopes…” data-image=” midioriginal/4 / 7/d/47dc2cafaf_59586_rust-screw.jpg” data-url=”” data-more=”Read More”>oxygen and general
Symbol: N Atomic number: 7 Electrons per energy level: 2.5 Atomic mass: 14,007 uIsotopes…” data-image=” 7 /a /57a531d2d3_50012051_suprazote.jpg” data-url=”” data-more=”Read more”>nitrogen). If a large part of the organic carbon on Earth has a biological origin, it can have non-biological origins, in particular meteorites, volcanic activity, or certain chemical reactions on the planet’s surface. The presence of organic carbon on Mars therefore in no way proves that life ever developed on this planet.

With liquid water, the presence of organic carbon in significant amounts is, on the other hand, a new element indicating that the basic ingredients necessary for life were present on Mars a few billion years ago. The Gale Crater in which Curiosity evolves would have been a place favorable enough for the appearance of lifesince in addition to water and carbon, the environment had the other essential elements: energy sources, low acidity, oxygen, nitrogen and sulfur.

So Curiosity could be in the right place to discover the long-sought first traces of Martian life. However, if they do exist, they might be more difficult to access than we thought.

Review the search strategy for organic molecules such as amino acids

A new experiment carried out by the POT in fact, it suggests that to have a chance of finding organic molecules, the rover should drill to a depth of two meters into the Martian subsurface. This refers particularly to the search for the structure of amino acids
Their name comes from the fact that they have an amine function (NH2) and a carboxylic acid function (COOH). They…” data-image=”” data-url=”https ://” data-more=”Read more”>amino acidsthat may or may not be of biological origin, but in all cases are considered building blocks for the construction of protein roles
Proteins can perform very diverse functions within the cell or the organism.
They may have:
a structural function (such as actin or tubulin that…” data-image=” – cc.jpg” data-url=”” data-more=”Read More”>protein. However, the conjugate acid and base
Every acid has a conjugate base…” data-image=”” data – url=”” data-more=”Read more”>acids Amino acids are fragile and easily destroyed by cosmic rays that reach the surface of Mars, the fine atmosphere does not provide effective protection. Currently, the rovers are drilling to a depth of five centimeters. Scientists estimate that at this depth, amino acids are destroyed in just 20 million years. Knowing that potential Martian life could have developed several billion years ago, investigating this very superficial level seems totally pointless.

These results, published in Astrobiology, show the need to implement a new search strategy for the rovers currently in operation, which unfortunately are not equipped to drill to the required depth. One solution would be to find outcrops having recently exposed deep parts of the subsurface, such as in small impact craters less than 10 million years old or in material ejected from such craters.

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