Gamma-ray bursts are a threat to life

Re:Gamma-ray bursts are a threat to life by eloff on Wednesday January 28, 2015 @11:39PM (#8964379)

It's tough to imagine a similar process in a complex lifeform. So it could well be the great filter. Evolution doesn't work well with things that happen rarely over geological timescales. This is one reason why life on earth is very sensitive to climate change, even although the climate has gone through many major changes in the past.

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Re:Gamma-ray bursts are a threat to life by jjoonathan on Thursday January 29, 2015 @12:00AM (#8964434)

I wouldn't expect the ability to evolve in Eukaryotes if a GRB happened near Earth, but I see no reason why frequent GRBs in a distant galaxy would put a ceiling on complexity. Here's how I see it going down:

1. Life evolves. Not radiation resistant except for a group of bacteria that like to hang out in uranium-rich soil (or something).

2. GRB. Radiation-resistant bacteria repopulate the planet.

3. Radiation-resistant mechanism breaks in 99% of bacteria, but vestiges remain.

4. Mechanisms to handle bigger genomes evolve (Let's call them "eukaryotes" for the sake of the argument).

5. Single-celled "eukaryotes" invade the uranium-rich soil ecosystem by fixing the vestigial radiation resistant genes.

6. GRB. Radiation-resistant prokaryotes and radiation-resistant "eukaryotes" repopulate the planet.

7. Rinse, repeat.

8. Eventually there will be big multi-cellular radiation-resistant "eukaryotes" walking aroud.

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> life on earth is very sensitive to climate change

We are very sensitive to climate change, as are a bunch of higher organisms we care greatly about. Life on Earth? Not a chance. We couldn't come close to sterilizing the planet if we wanted to.

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Re:Gamma-ray bursts are a threat to life by kirian on Thursday January 29, 2015 @08:17AM (#8965886)

How about a Tardigrade - not exactly a complex lifeform but a few steps up from a bacterium. I wonder if these creatures could survive this type of event? http://en.wikipedia.org/wiki/Tardigrade

"Tardigrades can survive in extreme environments. For example, they can withstand temperatures from just above absolute zero to well above the boiling point of water, pressures about six times greater than those found in the deepest ocean trenches, ionizing radiation at doses hundreds of times higher than the lethal dose for a human, and the vacuum of outer space. They can go without food or water for more than 10 years, drying out to the point where they are 3% or less water, only to rehydrate, forage, and reproduce."

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