What would happen if a gamma ray burst hit Earth?

"What would happen if a gamma ray burst hit Earth?"

Depends on the intensity and the duration.

"A long time ago I read about how a potential gamma ray burst could hit Earth within the next 500,000 years from 8,000 light years away. The worst case scenario would be about a 25% drop in Earth's ozone."

This is incorrect, not a mistake on your part. Gamma radiation will make *more* ozone, and lots of NOx. The sky will turn brownish, like smog, only it will be many kilometers thick.

"After searching into this I found that for every 1% decrease in ozone, UV B radiation would increase by 2%. This gives Earth a 50% increase in UV B radiation. Now, what this means, I don't know. Thats why I'm consulting you fine scientists out there."

Our experience with particle accelerators is such that we know *more* ozone is made. So now our atmosphere becomes (for a time) much more like that of Venus, optically thick, so we will be cooked like a foil wrapped potato in an oven.

"Now, obviously there would be an increase in skin cancer and obviously the side of Earth facing the gamma ray blast would be a little screwed, but what about the other side of Earth?"

We cannot lose much in the way of heat during the night. So temperatures will ratchet up...

"What would happen to Earth?"

A few hours to a day, and we'd survive. Much longer than that and all life on Earth will end.

"Would black people survive? Would lighter skinned people survive if they wore sunscreen outside all the time?"

Nope. It isn't UV from our Sun that will be the problem, because the atmospheric scientists made some wrong fundamental assumptions.

Thanks a lot! Very interesting

If a gamma ray burst hits us directly it's game over.