Gamma-ray bursts could play a key role , much more important than previously suspected, in the development of life, both on Earth and on other planets. This is how astrophysicists Tsvi Piran, from the Hebrew University of Jerusalem, and Raúl Jiménez, from Barcelona, put it in a study published in the journal Physical Review Letters .
These super-energetic bursts arise when a very violent cosmic event takes place , such as the collision of two neutron stars – which would give rise to a short gamma ray burst, lasting less than two seconds – or the formation of a supernova from a star much more massive than our sun – which would form a long flash -. These events generate shock waves and radiation emissions that, in theory, would have devastating effects on the organisms of the planets they reach. Although at the moment they have only been observed outside the Milky Way, they could also occur in our galaxy.
Piran and Jiménez suggest that gamma-ray bursts could not only be responsible for some of the extinctions that have occurred on Earth, but would also limit the very existence of life , especially in worlds closest to the center of their galaxies. , where they would occur most frequently.
According to these researchers, there is a 60% chance that one of these phenomena has caused an extinction on our planet in the last billion years. Moreover, they point out that it is possible that no living being, at least as they exist on Earth right now, could survive more than 5,000 million years ago, when galaxies were much more compact and these phenomena much more common. However, they indicate that early life forms would also be more resilient to radiation.
It is possible that the Earth was hit by one of these explosions 440 million years ago , when the Ordovician-Silurian mass extinctions took place, in which 85% of the animals perished. The ozone layer was probably destroyed then.
Photo: NASA
