In a previous blog post, I talked about how all of us are exposed to natural radiation on a daily basis. It mostly comes from space (called cosmic rays) as well as natural radioactive materials found in the soil, water and air. Some people were wondering what cosmic rays are.
Cosmic rays are actually energetically charged particles that originate in outer space (some from the Sun and some from elsewhere in the universe). About 90% of incoming cosmic rays are simple protons and 10% are helium nuclei. We’re protected from most of the cosmic rays by the earth’s magnetic field and also our atmosphere. Since our atmosphere provides some of our screening from these particles, the higher you go in the atmosphere the less protection you have. For that reason, there is slightly more exposure to cosmic radiation in Flagstaff when compared to Yuma (although the difference is of no health consequence).
So when I said earlier this month that if the situation in Japan would continue as-is for several weeks, the total exposure in N. America would be comparable to the amount of radiation that you would get flying from AZ to New York (about 0.04 milli-Sieverts- or about a 1% increase from average annual background), I was talking about the added radiation exposure you get from increased exposure to cosmic rays by spending time at 35,000 feet for a few hours.
I’m just curious what formula you used to come up with 1%?
Liny,
The average Arizonan gets 4 millisieverts per year and the I-131 exposure is projected to be about an increase of 0.04 millisieverts- so it’s a flat proportion.
These cosmic radiations are not dangerous for the health, but what about the japanese radiations ?
ckdo-
If there is enough radiation it can be dangerous, but there isn’t enough radiation coming from the tragedy in Japan to be considered dangerous.
hello ,
My name is daniel and I own nigerian forum
I’m an ardent reader of your posts and not just to leave leave without writing a comment this time around, I love the where you wrote ” Cosmic rays are actually energetically charged particles that originate in outer space (some from the Sun and some from elsewhere in the universe). About 90% of incoming cosmic rays are simple protons and 10% are helium nuclei. We’re protected from most of the cosmic rays by the earth’s magnetic field and also our atmosphere. Since our atmosphere provides some of our screening from these particles, the higher you go in the atmosphere the less protection you have. For that reason, there is slightly more exposure to cosmic radiation in Flagstaff when compared to Yuma (although the difference is of no health consequence). ”
Keep it up friend.
Do you have any longer-term projections for the risks?
– Dale
The high-energy cosmic rays bombard us all the time, but they interact quickly, producing particles of much lower energy which impact the earth harmlessly. If this was dangerous to us, we wouldn’t be here to discuss these things! Some particles, like neutrinos and high energy muons, are passing through us all the time, but they interact so weakly that they have no effect on our bodies. Of course, if we were in space without the protection of our atmosphere then we would need some other type of shielding from the radiation (spacesuits and protective covering on our spacecrafts).
The radiation to worry about, of course, is the ‘cosmic’ radiation produced by our sun. There is only one type of cosmic radiation known to adversely affect us and that’s UV radiation from our sun, which causes skin cancer in millions of people every year.. Again, our atmosphere serves as a shield, but ultraviolet photons do make it through — and without that protective ozone layer which blocks these photons we’re all going to need a lot more sunscreen!
So people that climb Mount Everest could return as mutants like on X-Men?