The last giant mega impact on earth may have been necessary for the appearance of life!

The reasons for the appearance of life on earth are one of the greatest puzzles in science in this 21st century. A new study However, comes to accredit the idea that its colossal impact with a planessimal, at the dawn of the solar system, has greatly contributed to this phenomenon.

Eight planets of the current solar system, only a accommodation today a life on its surface. As this appeared at least 3.8 billion years ago on earth, we must look for the causes of this biochemistry in a very distant past.

A chaotic solar system when it comes to its beginnings

The solar system is not this calm and ordered place that our short human existence leaves us accruing. He is violent and complex, but he was much more after his training. Billions of years ago, planets (or protoplanets) embryos struck themselves and could destroy themselves under the colossal power of these impacts.

In addition, the primordial element of all life on our floor of cows is to be carbon, an atom present in quantity in certain types of asteroids, which is called carboned chondrites (CC), whose samples fall on our heads in the form of meteorites. Many scientists believe that the contribution of these carbon chondrites meteorites has been decisive as a material necessary for life.

Thus, the mass of the earth would come for 5 to 10 % of this primordial material, much more than for Mars for whom estimates do not go beyond 4 %. We must therefore understand where this fundamental difference comes from. However, researchers think that these carbon -based meteorites could come from the gigantic impact between the earth and Théia, the planetsimal to whom we also owe – and indirectly – the existence of the moon.

These scientists have therefore programmed simulations, called N-corps, in the last stages of planet training to see if their hypothesis is factually credible. And the results are very interesting!

Théia, an impactor creator of life?

The researchers set up three scenarios with 10 different simulations per type. Here are the lessons they learn from it:

• The scenario of a set of small bodies of carbon chondrites is unlikely, because it should give the same proportions of carbon chondrites on Earth and Mars.
• The so -called “mixed” scenario corresponds very well to the current configuration of the solar system. The migration of giant planets, which also consensus, explains the orbital distribution of asteroids, the masses of rocky planets and the accretion of elements of the carbon chondrites.

In this “mixed” scenario, Théia would be the last giant impact on earth in 50 % of cases. Depending on the simulations, it could be a body of a pure carbon chondrite type, or a planetary embryo having accrected carbon chondrites during its formation. Here we pass certain details of the simulation such as that of the late accretion of the carboned chondrites, the essential to our eyes being that the hypothesis of a Théia having brought the elements necessary for life takes a little more weight.

Today there are still many possible variables for these crucial early times in the solar system, but it is certain that these computer simulations help to exclude less likely scenarios than others, such as a carbon chondrites contribution by many small elements over time.

It is thus a little more likely that terrestrial life owes its existence largely to this cataclysmic collision which also endowed us with the moon. Kiss cool effect: it is also estimated that the tides born with the latter played a major evolutionary role by promoting the evolution of marine organizations towards other terrestrials. Definitely, Théia will have changed everything for the earth …

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