The authors of the new study believe that once life takes hold in at least a small area of the planet,
In the search for life beyond the EarthAstronomers usually focus on a region known as the habitable zone. This is a region in orbit around a star where liquid water could potentially exist on the planet's surface. If the planet is closer to the star, it will evaporate; if further, it will turn into ice. None of these conditions are suitable for life as we know it.
But the habitable zone is only an approximation.a landmark, because both Mars and Venus are located there, but there is no life on these planets. The authors of the new study suggested that the generally accepted definition of a habitable zone may be too narrow because it does not include how life affects the world.
The earth would be completely different ifthere was no life on it. A classic example is the abundance of oxygen in the planet’s atmosphere. This is a very common element throughout the cosmos. But most of the “original” oxygen is bound in the form of silicon dioxide—rocks. Oxygen gas cannot exist in the atmosphere for long because it is destroyed by ultraviolet radiation from the Sun.
But in the process of photosynthesisOxygen gas is released as a by-product. In fact, early life produced so much oxygen that it was nearly "poisoned" during the Great Oxidation. It took the evolution of oxygen-breathing creatures to restore the balance of the ecosystem. In any case, it would be incredibly difficult for Earth to maintain this amount of atmospheric oxygen if not for the constant efforts of life.
This line of thinking can be applied to others as well.properties of the earth's atmosphere. Living things also emit large amounts of methane, a greenhouse gas that helps keep our planet warm. Forested areas change the amount of sunlight reflected from the surface, which also affects the world's temperature. Even the production of different gaseous by-products by different creatures can change the air pressure in a planet's atmosphere.
The authors of the new article presented the world at the very edgehabitable zone, either too cold or too hot. But if life had managed to originate there, it would have had a chance to improve the composition of the planet. Perhaps by increasing or decreasing atmospheric pressure or temperature, or by creating niches underground where life could flourish.
Therefore, scientists believe that traditionalthe idea of habitability criteria is worth reconsidering. They propose a new one: the habitable zone of Gaia (from Gaia, the Greek mythological personification of the Earth). It would be wider than what is considered suitable for life, because life itself is capable of changing the boundaries of “suitability” and turning an aggressive environment into a real “paradise,” explains a research professor in the field of astrophysics at SUNY Stony Brook University and the Flatiron Institute in New York. York.
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Cover illustration: Brad Sanford Sorensen, SS