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Somebody explain background radiation to me | by SnappingTurtle | 2004-10-21 14:37:37 |
| Radiation |
by rollingrock |
2004-10-21 14:58:36 |
| Radiation is a pretty general term. Generally it refers to any kind of emission, be it neutrons, alpha particles (basically helium), or electromagnetic radiation (light, radio waves, etc). The type and energy of the radiation is far more important than the amount of it you get. Neutrons can be very bad (like a neutron bomb), whereas alpha particles can be normally be stopped by paper. Background radiation could also mean a couple of things. When astronomers talk about it (this is the most common usage I believe), they are usually referring to electromagnetic radiation (microwaves) which is believed to be an "echo" of the big bang. The best data we have (I think) is from a satelite called COBE. Interestingly the microwave background is asymmetric, but thats a whole other discussion. There's also radiation from sun and other stars which constantly bombards earth. From the sun we get not only a spread of electromagnetic radiation, but also some charged subatomic particles which get picked up by Earth's magnetic field and dumped at the poles, giving us the Auroras. From other stars we get mostly electromagnetic. In a sense they keep timed plots of this sort of stuff since astronomers are always pointing their telescopes at something. But I dont think any sort of total is kept. This sort of thing is usually not something to worry about unless a supernova goes off nearby or the Earth's magnetic field suddenly disappears. Finally there's radiation given off by everything around us which someone might call background radiation, electromagentic as well as some other stuff. Granite in particular. Its always fun to take a geiger counter to the capitol and scare some senators. Anyway I think that about covers it. |
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