From my understanding, radiation is just gamma rays which are electromagnetic waves with really high frequency (and energy). While I do understand how they can be harmful when exposed to them (killing off cells etc.), I can’t wrap my head around how does something gets contaminated by radiation and continues to be radioactive sometimes for hundreds of years even when the source of the gamma rays is long gone.
In: Physics
Pre- tl:dr
If the radioactive contamination is cleaned up then there is no more risk of radiation. The “rays” quickly do their thing, then its over. If there is radiation then that means there is still a source somewhere. So without the radioactive material there is no radiation.
Longer but way more accurate explanation:
Radiation that causes damage is called “ionising radiation” and this includes gamma rays among others (like x-rays). When a “radioactive” material releases radiation it can also release “particle radiation” that is usually alpha or beta particles.
These alpha and beta particles along with gamma rays are the 3 most common types we think of when talking about “radioactive decay” of a substance (like uranium for example). As the radioactive substance goes through time it will randomly release one or more of these types of radiation. This release is what makes “radiation” dangerous to us.
After the particle or ray is released it quickly does it’s thing and that’s it. If something is “contaminated” then it means there is a radioactive material in or on it. That radioactive material that has contaminated something continues to release radiation, essentially forever. If all of the radioactive material is cleaned up then it is no longer “contaminated” and will release no more radiation (since there is no longer a source.)
Some radioactive substances have half-lives of billions of years, in essence making them highly radioactive forever.
Edit: Spelling and a few grammar mistakes that made part of this confusing
Latest Answers