Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Why is my dryer radioactive?

physics.stackexchange.com

Post reply on HN
Print view View original

141–150 of 170 posts

Re: Why is my dryer radioactive?

#141

Post by FormFollowsFunc »

misja111 wrote: post #138
antognini wrote: post #134

Earlier quoted context omitted.

Yes, this is why the idea to use Po-210 was a stroke of (evil) genius. Because of its unique decay profile it is extremely hard to detect. The FSB agents who did this could obtain a small but lethal dose of Po-210 in Russia and then carry it across borders dissolved in a vial of water. In that state it is not dangerous, so the agents had little risk to themselves by carrying it. And it is also undetectable by border…

Thanks for all the great insights! But why was the Po-210 not dangerous in that vial of water? It seems many people who got in touch with it got ill: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1767288/

According to another article the glass wall of the vial stops the radiation.

https://www.argonelectronics.com/blog/litvinenko-and-the-per...

Re: Why is my dryer radioactive?

#142

Post by rocqua »

axutio wrote: post #98
hackernewds wrote: post #97

Earlier quoted context omitted.

which means GPT will never be smarter than humans? same conclusion

No, but instead means that GPT can't be smarter than the people who are writing the published content on the web (generally, the very smartest humans if you're considering high quality published works alone). If you could do a perfect job of training a GPT on the entirety of published academic literature, the total of what that GPT could spit out would be limited by the knowledge contained in academic literature. At…

Whilst that is probably true, it is not necessarily true. Nothing fundamentally prevents GPT from synthesizing new and novel insights. If a novel insight is trivial to notice when combining knowledge from 4 disciplines, it could be neigh impossible for humans to find, and obvious to GPT.

Or perhaps the insight isn't trivial but follows analagous reasoning from some other obscure result. Or perhaps a million other things.

I don't mean to claim GPT will do this. I just mean to point out it can't be fully excluded GPT is able to.

Re: Why is my dryer radioactive?

#143

Post by jve »

BetterGeiger wrote: post #33

I think the core of the explanation given is correct but some of the adjacent details need adjustment. The important part is: "Clothes dryers are very effective at making statically charged surfaces. (Dryer sheets help.) So when radon and its temporary decay products are blown through the dryer, electrically-polarized molecules tend to be attracted to the charged surfaces" What that commenter misses is that nearly al…

What's the difference between alpha/beta/gamma and which is of concern?

Re: Why is my dryer radioactive?

#144

Post by jojobas »

antognini wrote: post #134
jojobas wrote: post #121

Earlier quoted context omitted.

Polonium-210 is a very rare example of near pure alpha-decay chain, radon decay products are short-lived and emit both beta and gamma particles.

Yes, this is why the idea to use Po-210 was a stroke of (evil) genius. Because of its unique decay profile it is extremely hard to detect. The FSB agents who did this could obtain a small but lethal dose of Po-210 in Russia and then carry it across borders dissolved in a vial of water. In that state it is not dangerous, so the agents had little risk to themselves by carrying it. And it is also undetectable by border…

When alpha particles are stopped by anything, secondary x-rays are created. I wonder if airport x-ray machines are sensitive enough to pick that up.

Re: Why is my dryer radioactive?

#145

Post by red75prime »

bcbrown wrote: post #137
Jun8 wrote: post #42

Earlier quoted context omitted.

The tidal bulge one is one my all time favorites, you should absolutely read the answer. tl;dr the simplistic view of two tidal bulges (that started with Newton) is wrong! This is one of those physics simplifications that still gets pushed around. For another example, see speed of light in glass is slower than vacuum.

> For another example, see speed of light in glass is slower than vacuum. I'd love for you to explain what you mean by this. Either you're mistaken or I'm about to learn something really interesting. Here's a link a quick search brought me, for reference. Are you talking about something other than refractive index, ratios of c, and prisms? Like a latency metric of some kind? I'm very curious. https://en.wikipedia.org…

It's probably that photons always propagate at c and that the apparent change of speed of light in glass is caused by photon absorption and delayed reemission by atoms (at least it's how perturbation theory of quantum electrodynamics describes the process).

Re: Why is my dryer radioactive?

#146

Post by codethief »

antognini wrote: post #130
jxf wrote: post #105

Earlier quoted context omitted.

How did it get detected?

His symptoms were consistent with radiation poisoning and because he was a high profile dissident his case attracted enough attention that the Atomic Weapons Establishment tested his blood and urine. They performed gamma ray spectroscopy but did not discover any strong signals, except for a very small spike at 803 keV. Some of the scientists were talking about the case and they were overheard by an older scientist wh…

> except for a very small spike at 803 keV. Some of the scientists were talking about the case and they were overheard by an older scientist who had worked on the UK's atomic weapons program back in the 50s. The early bombs relied on Po-210 and he recognized that 803 keV line as being characteristic of Po-210

I don't understand. So professionals from the AWE tried to identify the measured radiation lines from memory(?!), instead of consulting a publicly available database of spectral & decay lines? It's been a while since I've done any spectral analysis but I used to use ie.lbl.gov a lot (seems offline unfortunately) and they had a search function[0] that allowed you to filter their entire database of isotopes and decay chains by whatever line you were looking for.

[0]: https://web.archive.org/web/20150408041531/http://ie.lbl.gov...

Re: Why is my dryer radioactive?

#147

Post by fastneutron »

This is similar to a fun trick I used to show people back when CRTs were the predominant television screen. The face of the TV would build up a static charge and collect dust over time. I’d wipe the screen off with a damp paper towel and place it under a alpha/beta/gamma-sensitive Geiger probe. It would hit 500 counts per minute easily(background was about 250).

I knew people who took this to an extreme by putting a high-voltage static charge on a needle, then placing the charged needle in a closed bell jar with a pile of thorium-doped lantern mantles. The tip of the needle would pick up enough radon daughters that it made a great rechargeable point source for cloud chamber demonstrations.

Re: Why is my dryer radioactive?

#148

Post by gniv »

theGnuMe wrote: post #12
r3trohack3r wrote: post #2

We had this issue in the Midwest (central Illinois). Can’t remember exactly why, but radon would accumulate in the basements. Had to have sensors and ventilation for it.

Happens almost everywhere where basements exist.

I would think you want basements (and ventilate them), since otherwise the radon comes directly into the living space.

Re: Why is my dryer radioactive?

#150

Post by _Algernon_ »

jve wrote: post #143
BetterGeiger wrote: post #33

I think the core of the explanation given is correct but some of the adjacent details need adjustment. The important part is: "Clothes dryers are very effective at making statically charged surfaces. (Dryer sheets help.) So when radon and its temporary decay products are blown through the dryer, electrically-polarized molecules tend to be attracted to the charged surfaces" What that commenter misses is that nearly al…

What's the difference between alpha/beta/gamma and which is of concern?

Alpha has the shortest range and can be blocked by a piece of paper. Alpha radiation consists of protons.

Gamma goes through most things and has the highest range. Gamma consists of electro magnetic radiation.

Beta is somewhere in the middle. It consists of electrons.

All are of concern, but Alfa is mainly of concern if ingested or inhaled. This is because all the radiation will be absorbed by your body, while most gamma would just escape. Gamma is of more concern outside the body, due to its reach.

I may remember some details wrong. I last learned about this in school a decade ago.

Post reply on HN