Gamma equals omega

Gamma equals omega ››: Melott and co-workers ask, "Did a gamma-ray burst initiate the late Ordovician mass extinction?" in a paper submitted to the International Journal of Astrobiology. The abstract:

Gamma-ray bursts (hereafter GRB) produce a flux of radiation detectable across the observable Universe, and at least some of them are associated with galaxies. A GRB within our own galaxy could do considerable damage to the Earth's biosphere; rate estimates suggest that a dangerously near GRB should occur on average two or more times per billion years. At least five times in the history of life, the Earth experienced mass extinctions that eliminated a large percentage of the biota. Many possible causes have been documented, and GRB may also have contributed. The late Ordovician mass extinction approximately 440 million years ago may be at least partly the result of a GRB. A special feature of GRB in terms of terrestrial effects is a nearly impulsive energy input of order 10 s. Due to expected severe depletion of the ozone layer, intense solar ultraviolet radiation would result from a nearby GRB, and some of the patterns of extinction and survivorship at this time may be attributable to elevated levels of UV radiation reaching the Earth. In addition a GRB could trigger the global cooling which occurs at the end of the Ordovician period that follows an interval of relatively warm climate. Intense rapid cooling and glaciation at that time, previously identified as the probable cause of this mass extinction, may have resulted from a GRB.

It's just a tentative hypothesis, but an interesting one. The burst of energy from across the galaxy (perhaps already en route…) would manifest at the Earth's surface mostly as UV and last ten seconds or so. It would have an equivalent brightness in the UV range a couple of times what the sun has in the visible part of the spectrum but across the whole sky. In that brief moment, it would create as much nitric acid via atmospheric ionization as our most diligent polluting efforts have done over hundreds of years. And, depending on source proximity, undissipated energy and angle of incidence, it might just strip your cooked flesh from your bones in an instant. (This is better than the effects of a nearby supernova, which are pretty similar but occur as a slow crescendo taking several weeks rather than as ten hellish seconds). Best comment from the slashdot thread on this topic:

For a limited time I am offering heavy gamma screen lotion. This specially formulated lotion can provide you with protection for up to 12 seconds. Our lotion has been formulated with special serpentin oils and thus is guarented to work. We offer full money back after neutron star event,if your not satisfied.

Hemisphere lotto: the bulk of the planet would offer sufficient protection from the immediate blast but that is cold comfort. When it comes to ozone layers we all share just the one, and the prevailing winds will rapidly circulate the acid rain while global cooling will make things uncomfortable at all latitudes for centuries. I wonder: if we showed that some/most/all of the mass extinctions of the past were caused by gamma ray bursts, what would/could we do about it?; [Permalink…14-Apr-05…Deserving memes……Comments (0)]

Gamma equals omega

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