2014/09/08 by Tsvi Piran, Raul Jimenez, Raúl Jiménez · 1 voice · 76 citations
Biochemistry, Genetics and Molecular Biology · Physics and Astronomy · #Astronomy #Astrophysics #Extinction (optical mineralogy) #Galactic Center #Galaxy #Gamma-ray burst #Gamma-ray bursts and supernovae #Luminosity #Luminosity function #Milky Way #Mitochondrial Function and Pathology #Physics #Universe #astro-ph.CO #astro-ph.EP #astro-ph.GA #astro-ph.HE #astro-ph.SR
paper · pdf · doi:10.1103/physrevlett.113.231102
published in Physical Review Letters 113(23), 231102 (American Physical Society) · Version accepted to the Physical Review Letters
arxiv created 2014/11/13 · openalex publication_date 2014/12/05 · arxiv updated 2014/12/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
As a copious source of gamma rays, a nearby galactic gamma ray burst (GRB) can be a threat to life. Using recent determinations of the rate of GRBs, their luminosity function, and properties of their host galaxies, we estimate the probability that a life-threatening (lethal) GRB would take place. Amongst the different kinds of GRBs, long ones are most dangerous. There is a very good chance (but no certainty) that at least one lethal GRB took place during the past 5 gigayears close enough to Earth as to significantly damage life. There is a 50% chance that such a lethal GRB took place during the last 500×106 years, causing one of the major mass extinction events. Assuming that a similar level of radiation would be lethal to life on other exoplanets hosting life, we explore the potential effects of GRBs to life elsewhere in the Galaxy and the Universe. We find that the probability of a lethal GRB is much larger in the inner Milky Way (95% within a radius of 4 kpc from the galactic center), making it inhospitable to life. Only at the outskirts of the Milky Way, at more than 10 kpc from the galactic center, does this probability drop below 50%. When considering the Universe as a whole, the safest environments for life (similar to the one on Earth) are the lowest density regions in the outskirts of large galaxies, and life can exist in only ≈10% of galaxies. Remarkably, a cosmological constant is essential for such systems to exist. Furthermore, because of both the higher GRB rate and galaxies being smaller, life as it exists on Earth could not take place at z>0.5. Early life forms must have been much more resilient to radiation.