Radiation?

[spayss]

There's always a lot of discussion about radiation and it's damaging effects. What exactly does radiation do? I know it destroys cells, etc, but what exactly is going on? We hear about being bombarded by radiation but what is the physical 'happening' that's occuring? Is radiation like tiny bullets?

 

[nacnud]

<font color="yellow">Is radiation like tiny bullets?</font><br /><br />Yes and no.<br /><br />Broadly there are two forms of radiation, lumps of matter that are going very fast (particle radiation) and highly energetic light waves/photons (electromagnetic radiation).<br /><br />X rays, Gamma rays etc are highly energetic photons of light. There is no real way to shield against these except putting lots of material between you and the source. Even then only a proportion of the radiation will be stopped.<br /><br />The fast moving lumps of matter can be split further into charged and non charged particles. Charged particles, electrons or protons, can be shielded with material that has lots of charges in it. As lead has lots of protons in its nucleus it also has lots of electrons, as a charge particle moves through the lead these electron drag on the particle slowing it down. For a given energy of particle it is possible to stop all charged radiation with a set amount of matter.<br /><br />Uncharged particles need to actually hit something in order to stop and the most efficient energy transfer happens when they hit something as massive as themselves, like a proton. Therefore water makes a good neutron shield because of all the hydrogen it contains.<br />

 

[heyo]

I believe it can do things like.. for example.. a tiny sub-atomic particle can fly through a cell nucleus and smash a DNA molecule apart. Things like that.<br /><br />Somebody who knows more than me can probably answer better.<br /><br />I know it can cause cancer to develop later on in life, many years after exposure.<br /><br />Heyo

 

[spayss]

We often hear of the 'effects' of radiation but not the actual mechanism of damage. So it's the actual strands of DNA being physically destryoyed by electrons hitting them? Like a tiny projectile? The more projectiles, the more chance of damage.

 

[najab]

><i>So it's the actual strands of DNA being physically destryoyed by electrons hitting them?</i><p>That's one form of damage, yes. Also when a high-energy particle hits a large atom, the large atom undergoes fission. This doesn't lead to a runaway reaction (unless you're in the habit of eating large amounts of Uranium or Plutonium) but it does result in a shower of particles inside the body. In addition, there is thermal damage - the kinetic energy of the particle is converted to thermal energy inside the body - enough radiation and your organs can be cooked.</p>

 

[astrophoto]

Microwave, anyone?

 

[spayss]

Thanks for the education. It now makes more sense. I can see now how lifetime levels of exposure would have to be limited even after intervals of time. Even though the body repairs itself, the repairs may be faulty.