Our search for life beyond Earth is still in its infancy. We focus on Mars and, to a lesser extent, its oceanic moons such as Jupiter’s Europa and Saturn’s Enceladus. Should we expand our search to more unlikely places like molecular clouds? The idea that life might persist on other worlds, such as Mars or Europa, has gained momentum in the last few decades. Scientists have discovered that life on Earth persists in some extreme environments—hydrothermal vents, Antarctic ice floes, alkaline lakes, and even inside nuclear reactors.

In parallel with these discoveries, astronomers also found the chemical building blocks of life in space. They found amino acids inside meteorites, organic chemistry in the interstellar medium (ISM), and polycyclic aromatic hydrocarbons (PAHs) in molecular clouds. The discovery of extremists and the building block of life in space suggests that we must broaden the scope of our search for life. Should molecular clouds be one of our goals?

Molecular clouds are huge clouds of gas and dust from which stars form. Although they can contain many different compounds, they are called molecular clouds because they consist mostly of molecular hydrogen. Although clouds are filamentous in nature, they sometimes form denser clusters that turn into stars.

Could life exist in such a tenuous environment? One researcher believes this question is worth studying. In his paper “Possibilities of Methanogenic and Acetogenic Life in the Molecular Cloud,” Chinese researcher Lei Feng examines the idea that life arose in space as methanogens or acetogens, bacteria that produce methane and acetic acid as byproducts. According to Feng, these may have been the precursors of life on Earth. The document is available on the server ready to print arXiv.

“If methanogenic life exists in the presolar nebula, then it may be ancestral to life on Earth and is already [є] some of the previous ones [докази] several molecular biology studies,” Feng writes. (English is not Feng’s first language, but it is easy to understand what he means.)

Feng’s research is based on the idea of ​​panspermia. Panspermia is the idea that life exists in the universe and is spread by asteroids, comets, even cosmic dust and small planets. The history of life on Earth suggests that panspermia may have played a role, but we don’t know. This idea was purely speculative until scientists began finding the building blocks of life in space.

The main problem with life in molecular clouds has to do with temperature. It can be from 10 Kelvin to -263 Celsius. It’s too cold even for Earth’s extremists. There is also no solid surface, but this may not be enough to prohibit life. The most important factor in life, as we understand it, is that cells need fluid to carry out metabolic processes. Without water, cell membranes would have no structure, so there would be no way to keep the inside parts in and the outside parts out. So does the liquid have to be water? Could it be liquid hydrogen? Methane? We don’t know.

“Hydrogen molecules remain liquid between 13.99 K and 20.27 K, which is the typical temperature of molecular clouds,” Feng writes. “Assuming that life in molecular clouds has a cell membrane structure and hydrogen molecules (the main component of molecular clouds) are enriched in them, the pressure of hydrogen also increases and hydrogen can maintain a liquid state in life in molecular clouds.”

Feng explains that liquid hydrogen in molecular cloud (MCL) life could play the same role as water in life on Earth. “The state of liquid hydrogen is an ideal place for biochemical reactions, similar to the aqueous environment of cells on Earth,” he claims.

Life also needs energy, and life on Earth relies almost entirely on sunlight. Molecular clouds can be cold, dark places. How will Feng’s MCL obtain energy?

“How does molecular cloud life obtain enough energy? The author had previously proposed cosmic ray-driven bioenergetics, which works by ionizing hydrogen molecules,” Feng writes, citing his previous paper on the same topic. There may be other possibilities.

Life and reproduction require energy transformation. Earthly life depends on breathing. Respiration can be aerobic or anaerobic, meaning it uses oxygen or another electron acceptor. Methanogenic bacteria were among the first life forms on Earth and produced methane as a byproduct under hypoxic (low oxygen) conditions. In this process, they produce the free energy necessary for life. Scientists wondered whether methanogens could live on Saturn’s moon Titan. Can it survive in molecular clouds?

“Could methanogens survive on Titan, meaning they could also survive in molecular clouds? Here we discuss this possibility and calculate the free energy release for methanogenic life in the molecular cloud environment,” Feng writes.

According to Feng, calculations show that methanogenesis in molecular clouds can produce enough free energy for life. “From calculations, we found that the reaction of carbon monoxide, carbon dioxide, or acetylene with hydrogen molecules releases enough Gibbs free energy to allow the molecular cloud to survive,” Feng explains.

According to the author, this activity can even create biological signatures. “Consumption of carbon compounds throughout life may influence the distribution of organic molecules. This could be a possible tracer of molecular cloud life,” he writes.

Feng’s hypothesis is that life may have originated in molecular clouds and spread to Earth and elsewhere. He says methanogenic and acetogenic life may have been the ancestor of Earth’s LUCA, the last universal common ancestor. LUCA is the common ancestor cell from which three domains of life derive: bacteria, archaea, and the eukarium.

Never reject an idea hastily. We don’t know much about life, the universe, and everything else. Can we ignore Feng’s opinion? Unfortunately, Feng’s study lacks input from other researchers, which may be a sign that something is wrong. Some work by a single author has made significant contributions to science, often in the past. But they are becoming increasingly rare.

Feng’s hypothesis is an interesting and unusual idea. Thinking outside the box doesn’t always lead directly to new understanding, but it can encourage new ways of thinking. However, Feng’s work faces some obstacles. Molecular clouds have only existed for about 100 million years. Is there enough time? Also, LUCA is still just a hypothetical organism. Source