A galactic guide is ready to help astronomers study where and when life may have developed in the Milky Way, sheltered from violent cosmic explosions such as gamma-ray bursts and supernovae.
The guide, illustrated in the journal Astronomy & Astrophysics, was created by researchers led by Riccardo Spinelli, of the University of Insubria and associated with the National Institute of Astrophysics (INAF) in Milan.
The authors of the study analyzed the incidence of the most violent explosions in the universe during the evolution of our galaxy.
Thus, they demonstrated that over 6 billion years ago the peripheral regions of the Milky Way were the safest for the development of any life forms.
Then, with the passage of time, from 4 billion years ago onwards, the most central regions, including the one hosting the Solar System, became safer.
Safe up to a certain point, the experts point out, because the study supports the hypothesis that the first of the five great mass extinctions on Earth, which occurred about 445 million years ago, was caused precisely by a gamma-ray burst.
The energy released by gamma-ray bursts and supernovae is immense.
According to astrophysicists, a supernova releases as much energy as an entire galaxy like the Milky Way, and a gamma-ray burst can even emit in 10 seconds what a galaxy like ours releases in about 100 years.
For Spinelli, "if we exclude the very central regions of the Milky Way, less than 6,500 light-years from the galactic center, where supernova explosions occur most frequently, the study suggests that the evolutionary pressure in each epoch was mainly determined by gamma-ray bursts. .
Although they are much rarer events than supernovae - the scholar concludes - gamma-ray bursts are capable of causing a mass extinction from further away.
In fact, being the most energetic events, they are the bazooka with the longest range ".
