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It's not the gamma rays that kill you. In particular even with a supernova strength source, it's unlikely that the gamma rays would even have enough energy to g

It's not the gamma rays that kill you. In particular even with a supernova strength source, it's unlikely that the gamma rays would even have enough energy to get through the atmosphere to the point of meaningfully heating the ground. However, they would butcher and greatly change the atmosphere which, in turn, is what kills you - probably through a mechanism of massive amounts of UV and other high energy radiation now happily making its way down to us. As an example, a gamma ray burst is one possible hypothesis for the Ordovician extinction. Best case for survival would be to become multiplanetary. In particular the conditions that would be created would be survivable by the exact same technology that will be the baseline for human colonization on Mars.

bcherny 8y ago
> Best case for survival would be to become multiplanetary. How far away do you have to be to avoid getting gamma'd?
- cthalupa 8y ago
  Depends primarily on how far away it is. Scientists are pretty sure they're only 2-3 degrees wide at the source, so the closer you are, the less distance you would need to travel. Of course, the farther you are, the less energetic it is. So, if GRB are 2 degrees wide at the source, and it occurs 8000LY away, and is pointed directly at us, we'd need to travel 136LY away. The solar system is moving at 1/1300 the speed of light. I'm not sure how Apep is moving relative to us, but assuming it's stationary, we'd need ~175k years to move out of the crosshairs by sitting here on the planet.
a1369209993 8y ago
I have to admit, I was not expecting to have been underestimating the intensity of a gamma ray burst. > even with a supernova strength source In my defence, my reference power source was "supermassive black hole falling into another supermassive black hole" (probably due to having heard either GRBs in general or one specific one attributed to the collapse of a quasar).

bcherny 8y ago

> Best case for survival would be to become multiplanetary. How far away do you have to be to avoid getting gamma'd?

cthalupa 8y ago
Depends primarily on how far away it is. Scientists are pretty sure they're only 2-3 degrees wide at the source, so the closer you are, the less distance you would need to travel. Of course, the farther you are, the less energetic it is. So, if GRB are 2 degrees wide at the source, and it occurs 8000LY away, and is pointed directly at us, we'd need to travel 136LY away. The solar system is moving at 1/1300 the speed of light. I'm not sure how Apep is moving relative to us, but assuming it's stationary, we'd need ~175k years to move out of the crosshairs by sitting here on the planet.

a1369209993 8y ago

I have to admit, I was not expecting to have been underestimating the intensity of a gamma ray burst. > even with a supernova strength source In my defence, my reference power source was "supermassive black hole falling into another supermassive black hole" (probably due to having heard either GRBs in general or one specific one attributed to the collapse of a quasar).