Suppose an extinction level event occurs at high noon on one side of Earth, and at that moment, you are on the midnight side of the world.
Would you still suffer radiation poisoning?
Would the “fried side” die-off bring the rest of the planet with it?
Not my area of expertise, but I’ve read that a gamma ray burst would affect a lot of the oxygen and nitrogen in the atmosphere at higher altitudes, creating a lot of nitrous oxide type chemicals that would wipe out the ozone layer. The earth itself would shield you from direct radiation from the gamma ray burst, but the massive damage to the ozone layer would remove its protection. That is going to end up causing massive damage world-wide.
No, you yourself would not be exposed to any radiation.
Yes, by definition, an extinction level GRB would cause massive extinctions.
The NO[sub]x[/sub] would also render the atmosphere largely opaque, which would have serious effects once it mixed up well. And I’m not sure what the epidemiological implications would be of having one hemisphere flash-sterilized: That’ll leave a lot of dead meat in that hemisphere, which would soon be recolonized by rotting bacteria, fungi, etc.
Although FWIW, it is almost impossible to kill literally everything on Earth. All the previous mass extinctions really just opened up opportunities for the surviving life-forms to fill the newly vacant niches. Even if a disaster killed all humans and 99.9% of the animals, fish, birds, and plants on Earth, there would still be bacterial colonies living in the deepest parts of the oceans. The planet went from 0 to 60 once, it can do it again.
Might take a while, though.
Let’s not forget the effects on the Man in the Moon Marigolds either.
Gamma rays disassociates water into H[sub]2[/sub] and O[sub]2[/sub] … one little spark and poof … the atmosphere catches fire …
We only get so many do overs though. The sun ain’t getting any younger, and long before the sun starts to expand into a red giant, it’s going to get hot enough to vaporize the oceans. Before that happens, we’re due for another ice age. It’s unlikely the Earth is going to produce another potentially space-faring race in the time it has left.
Does it even need a spark if the concentrations are high enough?
In his book “Death from the Skies!” Dr. Phil Plait (an esteemed former Doper) says that along with the outright killing on the side facing the burst, the N02 smog formed would cause an ice age, and the ozone depletion would wreck the food chain.
How long would it take between GRB hitting and total ecological collapse?
Let’s posit a best-case scenario: We’ve been building enough FTL spaceships for everyone to get off the planet. The gamma-ray burst happens unexpectedly, but everyone on the “safe” side (that is, not hit directly) is alerted the minute it happens.
Do they have enough time to get to their ships?
(If so, it might be time to change up the Superman origin story. This is a much more gripping scenario than the original reason Krypton exploded, which was “just 'cause”)
Is there any evidence that one has struck the Earth before? AFAIK, none of of the major extinctions were due to one, perhaps one of the lesser ones? What kind of evidence would there be in the fossil record?
Which doesn’t release any more energy than the original gamma rays did.
How long would NO2 stay in the atmosphere, though? Wouldn’t it condense out, create acid rain etc. fairly quickly?
The evidence is a bit iffy, but during one major extinction event about 450 million years ago, trilobites that lived in deep water survived in much higher numbers than trilobites that lived in shallow water, even though the shallow water trilobites were much more numerous. During most types of extinction events, you’d expect the more numerous populations to have a greater survival rate. A gamma ray burst would affect things living in shallow water (and on the surface) more than things living in deep water, and hence this has been proposed as a possible explanation for what is seen in the trilobite fossil record.
Wikipedia’s article on the extinction event mentions the gamma ray theory but doesn’t go into much detail about it:
What about geographical patterns in that trilobite extinction? Were there greater numbers of extinctions in what would then have been a single hemisphere of the world? Did the depth correlation only show up in that one hemisphere?
No direct evidence, but based on the frequency of them, the Earth should find itself in the path of a GRB once or twice every billion years. The Ordovician extinction engineer_comp_geek mentions fits the bill with a die off of shallow water organisms.