Supermassive black holes could help with the development of life
The most massive black holes can cover galaxies with immense radiation. However, this need not be harmful for possible extraterrestrial life.
Artist's impression of a particularly bright active galactic nucleus, a quasar
(Image: ESO/M. Kornmesser)
Active, supermassive black holes that cover galaxies with high-energy radiation from their centers could not be an obstacle to the development of life, but could even help it. This is suggested by the research work of a research group, which describes the result as "surprising". The immense radiation could contribute to the success of life instead of ensuring that evolved species "fall into oblivion". According to their simulations, the radiation could ensure that once an atmosphere has been created with oxygen, it would quickly be enriched with ozone. This would then protect living organisms from harmful influences from space and make a biosphere more resilient.
But radiation makes it more difficult for life to develop
Supermassive black holes, which accelerate matter enormously in the center of galaxies and cause it to radiate, form so-called active galactic nuclei (AGN). They are among the brightest objects in the universe and it should actually be assumed that the immense amount of radiation is too great for comparatively nearby stars and their planetary systems to enable the emergence of life there. However, the research group led by Kendall Sippy from Dartmouth College in Hanover, New Hampshire, has now determined that although the distance to such objects is not insignificant, worlds in these galaxies can certainly benefit from such an active galactic nucleus.
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Simulations have shown that life would have to emerge for the positive effects and enrich the atmosphere of a planet with oxygen. Once this has happened, the immense radiation could have a positive effect by triggering the chemical reactions that cause the ozone layer to grow. The thicker it is, the more harmful radiation it keeps out. This also used to happen on Earth, but to a much lesser extent. It was only through the sun's radiation that the protective layer took on the dimensions that were necessary for the development of complex life. The work is presented in The Astrophysical Journal.
The team also writes that Earth is too far away from the central black hole in our galaxy to feel the effect described, even if it were to suddenly become active. Even if an active galactic nucleus were to appear much closer, the ozone layer would grow so strongly within a few days due to the radiation that we would be protected again. The team was therefore surprised at how quickly this would happen. At the same time, however, it also points out that the radiation from such a supermassive black hole would probably have prevented the emergence of life here. So this barrier remains, and it is unclear how it could be overcome in order to get oxygen into the atmosphere in the first place.
(mho)
