Exobiology: what if there were silicon-based life forms?

An American laboratory has achieved an incredible feat: developing a bacterium capable of producing molecules containing silicon. This is a great first since this element does not exist in nature in a pure state, although it makes up more than a quarter of the earth’s crust. This proves that other forms of life could possibly have developed on a basis of silicon and not of carbon as on Earth.

Chemists at the California Institute of Technology (Caltech) have manipulated a cytochrome C and obtained a bacterium capable of establishing a chemical link between carbon and silicon atoms. These links are well known to scientists, whether in the composition of the earth’s crust, but also in manufactured products from the pharmaceutical and electronic industries.

What if extraterrestrial biological systems had developed on a basis of silicon? In any case, this is what these American chemists think (with some reserve). Indeed, silicon is capable, like carbon, of bonding with four distinct bonds forming a tetrahedron of which the atom is the center. Thus, such a configuration can give development of complex molecules in three dimensions. However, silicon is chemically poorer than carbon, which has a higher electron charge.

The possibility of a planet where life would have developed on a base of silicon is unlikely, but you never know. Be that as it may, chemists have succeeded in creating this bacterium capable of producing molecules containing silicon, whereas no other is capable of doing so on our planet in its natural state. The content of their experiment was reported in the journal Science on November 25, 2016.

This experience is also reminiscent of the declarations of a certain Carl Sagan in 1973. This American scientist and astronomer who is also one of the founders of exobiology then evoked the « chauvinism of carbon », that is to say the fact that the human species tends to think that life as we know it can only be based on the chemistry of carbon.

Sources: Futura Sciences – The New Factory

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