Filed under: Astronomy, Fermi's Paradox, General Musings, Science, Science Fiction, SETI, Space, Survival | Tags: astronomy, blogging, Drake Equation, exoplanets, Fermi's Paradox, gamma ray bursts, Harvard, Hebrew University, jim downey, life, physics, Raul Jimenez, science, Science Fiction, SETI, space, survival, Tsvi Piran
It really does seem to be a pretty universal law:
On the role of GRBs on life extinction in the Universe
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 Gyr 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 Myr 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.
What that means is summed up in this article. Here’s the conclusion:
Astronomers have long known that the Earth occupies a unique position in the solar system that allows life to flourish. This idea of a habitable zone now allows them to focus search for exoplanets that might also have conditions that are right for life. Now they can take this further by excluding inhospitable regions of the galaxy, and searching only those stars and galaxies that exist in the universe’s habitable zones.
Of course, that’s just for life as we know it …
Jim Downey
Communion Of Dreams 