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Mark H
Earth hit by a gamma-ray burst: Did a cosmic blast hit us in 775 AD? - http://www.slate.com/blogs...
Earth hit by a gamma-ray burst: Did a cosmic blast hit us in 775 AD?
Earth hit by a gamma-ray burst: Did a cosmic blast hit us in 775 AD?
"Imagine two massive stars orbiting each other. One ends its life as a supernova. The core collapses, but doesn’t have the oomph needed to make a black hole. Instead, it forms a neutron star, an incredibly dense ball of neutron a few kilometers across but with the mass of the Sun. Then, sometime later, the second star explodes and also forms a neutron star. The two compact and ridiculously dense objects orbit each other, and over time (due to complicated relativistic effects) the orbit decays. The two neutron stars get closer, until, eventually, they get so close they merge. The gravity of either star is a billion times that of Earth, so when they merge, it’s a fiercely violent event. There’s a huge explosion, and again you get those twin beams of energy blasting out." - Mark H from Bookmarklet
"If one of those went off now at that distance, it would be bad. Our atmosphere would absorb all the radiation and we’d be safe enough from all that here on Earth’s surface, but we’d lose satellites, the interaction of the high-energy gamma rays would blow out power grids all over the planet, and our civilization would be in big trouble. But remember, these events are very, very unlikely. So much so that I’m still skeptical a GRB was the culprit in this case! And no matter what it was, it must’ve been pretty rare. " - Mark H