We have always imagined active supermassive black holes (AGN) as Cosmic devourorsextreme radiation sources capable of annihilating everything around them. But a new study published in The Astrophysical Journal challenges this vision since under certain conditions, the intense radiation of these galactic monsters It could actually favor life.
Dartmouth College researchers and Exeter University have discovered that the effect of an AGN on life depends on two key factors: The distance from the planet to the radiation source and the composition of its atmosphere.
“Once life has oxygenated the atmosphere, the Ultraviolet radiation It is no longer a devastating threat and, surprisingly, it could even benefit the planet, “explains Kendall Sippy, lead author of the Dartmouth study and researcher.
To reach this conclusion, scientists made simulations on Earth and exoplanets with similar atmospheres. They discovered that, if oxygen was already present, the radiation induced chemical reactions that encouraged ozone formation, an essential gas for protection against ultraviolet radiation. In other words, how much More oxygen in the atmospheregreater would be the protective shield allowing life to prosper.
A key episode of Earth’s history
This phenomenon recalls a key episode of the history of the earth since about two billion years ago, the first photosynthetic microorganisms They began to release oxygenwhich allowed the accumulation of ozone and protection against solar radiation. According to researchers, if a planet manages to oxygenate its atmosphere quick enough, the Ozone could stabilize your surroundings and favor the development of more complex life forms.
But what would happen if the earth was much closer to an active AGN? To answer this question, scientists simulated a scenario in which the Earth’s atmosphere did not have oxygenas in the archaic era. In that case, extreme radiation would prevent life formation. However, if oxygen were present, the ozone layer would be formed in a matter of days, protecting the surface of the planet with an unexpected speed.
“Us The speed surprised with which Ozone would respond to the increase in oxygen, “says Jake Eager-NASH, co-author of the study and currently a researcher at the University of Victoria.
The evolution of life in the universe
For now, the earth is too far from its central black hole, Sagittarius A*as to experience these effects. But this finding suggests that the AGN could play a more complex role in the evolution of life in the universe. Instead of being only heralds of destruction, they could, under the appropriate conditions, become Unexpected Guardians of Habitability Planetary
Study findings not only challenge the classical vision of the AGN as destroyers of worldsbut also open new questions about the conditions that allow life in the universe.
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