Don't be afraid of GRBs
In principle, the concern is justified: A gamma-ray burst in our galaxy could have fatal consequences for life on earth (animation: the distant GRB060218, upper edge of the image). These explosions occur when massive stars go supernovae and collapse into black holes. More energy is released within seconds to minutes than the sun did in its entire lifespan of more than ten billion years.
According to a team of astronomers led by Krzysztof Stanek from the Ohio State University, the reason why we can still look calmly into the future is that there are simply no stars in the Milky Way, which at the end are long-lasting and therefore dangerous Gamma Ray Bursts (GRB) could emit.
The researchers analyzed four such GRBs in surrounding galaxies and found that the stars in the systems consist primarily of the light elements hydrogen and helium. However, heavier elements, which only form after many stellar generations, could hardly be found. Our galaxy, on the other hand, is so old that its stars contain large amounts of heavier elements. And according to the theory, they lose so much matter during their lifetime that their mass is ultimately not sufficient to produce long-lasting GRBs. >> JS