Science Magazine describes a provoking paper by Piran (HUJI Jerusalem) and Jimenez (U. Barcelona, Harvard) accepted for publication to prestigious Physical Review Letters two weeks ago:
Complex life may be possible in only 10% of all galaxies (Science)The basic claim is rather simple.
On the role of GRBs on life extinction in the Universe (arXiv, PRL)
This extraterrestrial citizen works with Alza.cz and Alza.sk and spreads tablets and other things all over our homelands. The negative feedback suggests that the Czechoslovak folks may suffer from green xenophobia, after all.
The extraterrestrial ethnic minorities face another problem: (long) gamma-ray bursts, likely to be close to centers of small enough galaxies, take place too often and kill (the ozone layer and) complex life too early. Only 10% of galaxies – typically those that are large enough and sufficiently metallic, similarly to the Milky Way – has a chance to pass this cataclysmic test, and life seems to have a chance far away from the center only.