Three main theories. How life emerged on Earth: Scientists believe they are closer to the answer

Of all the questions science tries to answer, one of the most important is how life began on Earth. There are now three main theories explaining this, and based on these theories, scientists believe they are closer to solving one of the main mysteries of our planet, writes the Daily Mail.

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Three main theories regarding the origin of life on Earth:

• The first theory is called the primordial soup theory and proposes that the chemical building blocks of life formed from elemental gases and metals in shallow bodies of water on the early Earth;
• The second theory, called the panspermia theory, suggests that meteorites brought living microbes to Earth and they spread across the planet;
• The third theory is called the pseudopanspermia theory and suggests that meteors or comets, not living things, brought the basic building blocks of life to Earth. These molecules settled in the first seas and gave rise to single-celled organisms.

Experts in the field of astrobiology and chemistry believe that the most likely explanation for the emergence of life on Earth is a combination of the first and third theories.

Important

According to Graham Cooks from Purdue University in the USA, the molecules of life on Earth include proteins and nucleic acids (RNA and DNA). Whether these molecules are created on Earth or elsewhere, the chemical reactions that lead to their formation will be the same.

Cooks believes that the building blocks of life may have emerged from the combination of the pseudopanspermia theory and the primordial soup theory. Meteorites carrying the building blocks of life hit amino acids and other molecules accumulated in ancient water bodies on Earth and began to form the basis of life on the planet in the form of proteins. At least that’s what laboratory experiments show. However, it is not entirely clear whether this is actually the case.

Yasuhiro Oba, also of Hokkaido University in Japan, acknowledges the shortcomings of the pseudopanspermia theory but thinks it is more likely. Creating amino acids that mimic early Earth under laboratory conditions is a big deal, Oba said. But the emergence of real creatures is a completely different thing. Another problem is that scientists do not know exactly what the real environment of the early Earth was like.

Oba and his colleagues discovered that basic organic molecules can form in space. These molecules, called nucleosomes, combine with phosphates and sugars to form the nucleotides that make up DNA, so they are far from real living things. But they are necessary for life.

According to Oba, processes created in the laboratory can lead to the formation of molecular precursors to life, improving the understanding of the early stages of chemical evolution in space.

Scientists have also discovered that amino acids can form in space, but it is difficult to say with certainty that the pseudopanspermia theory explains the emergence of life on Earth better than the primordial soup theory. However, Oba does not rule out the possibility of a combination of these theories.

The theory of panspermia is much simpler than the other two theories, and with its help it is the easiest to explain the emergence of life on Earth. According to Japanese atrobiologist Yuko Kawagushi, according to this theory, a meteorite (or meteorites) broke off from a planet, flew through space and landed on Earth. Scientists have already found that it is possible to transport bacteria into space where they can survive for 2-8 years. But such bacteria can remain unharmed. However, in this case, it is not yet clear where exactly these microbes come from.

Scientists agree that the building blocks of life existed on Earth before life emerged. And these components came to Earth from space or were already present on Earth. Future comprehensive studies into the origins of life on our planet should answer this question, the researchers say.

As I already wrote FocusA British architect has presented a futuristic concept for a space elevator that could be used to enter orbit in the future.