A new study showed why life on Earth is a coincidence

Life on Earth may have become possible thanks to a very narrow window of conditions that existed during the planet's formation. According to research, without the proper balance of oxygen, two essential biological substances — phosphorus and nitrogen — would not accumulate near the surface, making it impossible for life to begin.

Space magazine discusses this phenomenon.

Is the formation of life on Earth a coincidence?

The authors of the study concluded that Earth formed under a uniquely precise set of chemical conditions that allowed two critical elements for life as we know it to remain on the surface: phosphorus and nitrogen. A rocky planet may appear habitable on the surface but be chemically "empty" for biology if these elements are absent or unavailable.

During the early stages of evolution, young planets are often partially or completely molten. During this period, heavy metals sink inward and form a core, while lighter substances remain closer to the surface. The level of oxygen becomes decisive precisely during this phase: it determines where the other elements "settle" and whether they remain in the mantle and crust, where they will be accessible for future life-related chemistry.

According to models, the level of oxygen must fall within a very narrow range. If there is too little oxygen, phosphorus is more likely to bond with iron and "fall" into the core. This deprives the surface of a key component of DNA, cell membranes, and energy transport. Conversely, if there is too much oxygen, nitrogen is more easily lost to space. Ultimately, the necessary set of "building blocks" does not form.

Researchers named this intermediate level of oxygen the "Goldilocks zone" and claim that Earth is right within its limits. If there had been even a little more or less oxygen during the formation of the core, there would not have been enough phosphorus or nitrogen for life to develop on the planet.

In their modeling, the team compared these conditions with those of other planets, including Mars. According to the authors, the chemical balance was different there: more phosphorus could have been preserved in the mantle, but less nitrogen. This makes the environment difficult for life as we know it.

The study calls into question the conventional emphasis on the "habitable zone," the area around a star where liquid water can exist. While water remains critical, this may be insufficient; a planet can be at the right distance from a star and still lack the internal chemical "supply" necessary for life to emerge.

The key point is that the conditions determining this process are related to the star's chemical composition. Since planets form from the same material as their stars, stellar "chemistry" can indicate whether a system is capable of producing planets with a balance of elements conducive to life. The authors believe this could make the search for life more precise; it is worth paying attention to systems with stars similar to the Sun.

Read more:

Jupiter is not what we thought it was — scientific research

The interstellar comet 3I/ATLAS has unexpectedly changed — photo