Chinese astronomers at the Zijinshan Observatory are developing the idea that life could arise in molecular clouds. His new calculations show that conditions in these stellar cradles are suitable for methanogens to survive.
Molecular clouds are regions of very high density of substances where molecules can form, especially hydrogen and carbon monoxide. And these are exactly the compounds that methanogens use for important purposes. On Earth, these single-celled organisms live primarily in anoxic conditions and produce methane throughout their lives. As experiments have shown, they can survive even in the most extreme conditions, and could even survive in simulations of conditions on Mars and, in theory, on moons and small icy bodies in our solar system. Therefore, scientists believe that methanogens could be a trigger for the panspermia scenario.
Chinese astronomer Lei Feng proposed going a step further and considering the possibility that life arose from the molecular cloud from which our solar system later emerged. The normal temperature of such clouds is between 10 and 20 Kelvin. “Warm” clouds can reach 20 to 60 Kelvin, and some even reach 100 Kelvin. In his research, Lei Feng estimated the possible changes in the internal energy (Gibbs free energy) of a molecular cloud during the formation of methane, water, and acetic acid from hydrogen, acetylene, and carbon dioxide, ranging from 10 to 100 Kelvin. Calculated using range.
The minimum amount of free energy required for methanogens to survive on Earth is 42 kilojoules per mole, but astronomers have calculated that in dense molecular clouds the free energy ranges from 60 to 370 kilojoules per mole. It should be kilojoules. I mean, that should be enough. As the authors pointed out, carbon dioxide exists in solid form in a molecular cloud. Methanogenic and acetogenic life forms can attach to these grains, making energy and carbon available. The life activity of single-celled organisms should then influence the distribution of carbon molecules within the molecular cloud. And based on these signs, scientists’ hypotheses can be confirmed.
When it comes to panspermia, methanogens are good candidates. In his 2016 study published in Nature Microbiology, scientists examined 6.1 million protein-coding genes in the genomes of modern prokaryotes. The researchers concluded that the first life forms on Earth resembled methanogens and anaerobic bacteria of the Clostridium class. Of course, scientific research in this field continues. Nevertheless, Earth’s primordial atmosphere must have attracted “unicellular cloud life.” It contained large amounts of carbon monoxide and carbon dioxide.