Scientists have revised the hypothesis of the origin of life on Earth

More than 4 billion years ago, the young Sun was 25-27% less bright than it is today. With this amount of solar radiation, the Earth, according to calculations, should have turned into a frozen ball, but geological data indicate the existence of liquid water. The new model, presented in the journal Universe Today, suggests that the planet could have been covered with ice almost entirely, and the conditions for the appearance of life were preserved near the equator. How solar flares could have helped the early Earth to warm up and create conditions for complex chemistry is described in the Izvestia article.

The earth could have started with cold

Astrophysicist Vladimir Hayrapetyan from the Goddard Space Flight Center of the National Aeronautics and Space Administration (NASA) said at the recent Origins 2026 conference that one of the main mysteries of the origin of life is related to how the early Earth was able to retain liquid water with a weak young Sun.

However, another question remained: where did the energy needed to break down nitrogen molecules and form more complex organic compounds come from? According to the researchers, one of the possible sources could be powerful solar flares.

Young stars are capable of producing powerful outbursts accompanied by coronal mass ejections. As a result, high-energy protons are formed, which could reach the atmosphere of the early Earth. When they collided with nitrogen and carbon dioxide molecules, they could contribute to their destruction and trigger the chemical processes necessary for the formation of more complex compounds.

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How could an icy planet conserve water

One of the problems with the early Earth scenario is the need to simultaneously explain the presence of liquid water and avoid too much greenhouse effect. If there were enough carbon dioxide to warm the planet, it could enter small bodies of water and make them too acidic for the chemistry needed in the early stages of life.

Hayrapetyan and his colleagues used nitrous oxide — N₂O in their model. With a concentration of about 10% of this gas in the atmosphere, calculations showed that the Earth's equatorial belt could warm up to +2-3 degrees. At the same time, most of the planet would remain covered with ice. Researchers call this scenario the "cold start" of life.

According to the publication, in these conditions, small areas of liquid water could become a place for chemical reactions. Moreover, the cold environment could prevent some organic compounds from evaporating. In particular, we are talking about hydrogen cyanide, a compound that is considered an important participant in prebiotic chemistry. According to the researchers' model, it could persist in small lakes and participate in further reactions that contribute to the complication of organic molecules.

The researcher also draws attention to the importance of alkaline conditions. As an example, he cites boron, which is necessary for the stabilization of ribose, a molecule that plays an important role in the formation of RNA. According to Hayrapetyan, the formation of stable information molecules of RNA and DNA is impossible without ribose.

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What solar flares say about life on other planets

Researchers are still unable to establish exactly when and how life appeared on Earth. Hayrapetyan notes that in the coming decades, scientists will be able to use new ground-based and space-based telescopes to search for biosignatures on rocky planets orbiting stars similar to the Sun.

At the same time, the scientist suggests looking not only for signs of pre-existing life, but also for so-called prebiotic signatures. In particular, nitrous oxide in the atmospheres of distant planets may attract attention. Its presence could indicate the presence of atomic nitrogen, capable of binding to other chemical elements and participating in the formation of complex molecules.