How would humans react to living in an atmosphere that consists of 0.002% of radiation?
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I'm sorry, but the question makes no sense as worded. "Radiation" is not a gas so it can't be a component of an atmosphere. Can you reword?
In this context "radiation" refers to high energy particles or EM radiation that are emitted from radioactive decay, so it can't make up part of the atmosphere. Instead, there would be unstable, radioactive isotopes that decay and emit radiation. How people would respond to this highly depends on the specific radioactive isotopes that make up this 0.002% of the atmosphere.
I'm sorry I don't know anything about science so I don't know how to word things.
Radiation that kills people.
How much would have to be exposed to someone so that they have 15 years to live?
Well what different types of radioactive isotopes are there?
There's no simple answer to that question - too many variables. You might try this wikipedia article, follow some of the links and references from there.
Lots. Most elements have multiple isotopes, some of which are radioactive. Google "radioactive isotopes", read what you find, come back here with some more specific questions and you'll get better answers.
Well, if you look at this chart of the isotopes: http://www.nndc.bnl.gov/chart/, each box represents one of the known isotopes of elements that physicists have measured in some way. Now, the black boxes are the only ones that are stable. So, actually, most of the isotopes we know are radioactive. But, then again, most of these you'll never see on Earth. (Many of them you will see in astrophysical environments though).
However, if you're interested in this for a story, you're going to want to think about what possible isotopes could be released into the atmosphere to cause damage. So you should research what can be released from a fission weapon - that will reduce the pool of isotopes.
Then! You need to consider the biological effects of these isotopes. Different isotopes obviously have different chemistry and different ways of bio-accumulation - iodine is taken up by the thyroid, and strontium is taken up by bones, so have different effects, and require different amounts to do damage.
Then! You should look at some of the data about what thresholds are considered dangerous. In radiation safety, there are sort of two different ways you consider damage - direct effects (radiation sickness from very large doses), and stochastic effects from small doses (e.g. cancer). Anything that kills you in 15 years is a stochastic effect, and there is no way that everyone will die at once.
If it helps, the rough rule of thumb is that 1 μSv of radiation (remember that Sv depends on the type of radiation) increases your risk of cancer by one part in 21,000,000 (21 million), increases the risk of severe hereditary effects by one part in 125,000,000 (125 million) and has a total risk of one part in 18 million.
But the effect of radiation on people is a super super complicated (super interesting and super important) business, and you should really do some more research and think about it.
Would I be right in thinking that this is about a scenario for a SF story?
This thread should probably be merged with his other one in the sci fi forum.
As long as the thread stays on the topic of radiation exposure, I'm content to leave it here. Any talk of the story details or anything having to do with creating a story will need to be in a thread in the sci-fi forum.
Ha. That's why I asked the reason for the question.
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