61–70 of 77 posts
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It's U-238, so the half-life is about 4.6 Billion years. Not totally stable, but pretty damn stable.
I don't think stable refers to the half life. It's a binary status.
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I don't think stable refers to the half life. It's a binary status.
Good point; it would be interesting to calculate how many atoms per second disintegrate in, say, one gram of the "relatively stable" U-238 - my guess is, quite a few!
²³⁸U has an atomic mass of 238.05078826, so one mole of ²³⁸U weighs 238.05078826g. One mole means the Avagadro number of atoms, 6.02214076×10²³.
Dividing by 238.05078826 gives 1g of ²³⁸U having 2.52977×10²¹ atoms.
²³⁸U's half life of 4.468 billion years is 1.4099635×10¹⁷ seconds, so in 1 second
6.02214076e23/238.05078826*2^(-1/1.4099635e17)
https://www.wolframalpha.com/input/?i=6.02214076e23+%2F+238....
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So the crucifix is visible in the dark? This article makes it sound like a black light needed to observe the phenomenon, which strikes me as odd because I wouldn't have thought black lights were commonly available at the time when these first gained popularity.
The crucifix is different, besides the Uranium glass it has engravings painted with something I think is tritium.
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Would that be cryptographically secure? Couldn't someone perturb an RNG based on background radiation by beaming radiation at it?
That shouldn't change anything: https://en.wikipedia.org/wiki/Fair_coin#Fair_results_from_a_...
There have been quite a few photographic lenses containing radioisotopes: https://camerapedia.fandom.com/wiki/Radioactive_lenses A few years ago I sent an Olympus Zuiko 55mm 1.2 to a friend in Russia. It has thorium in its glass elements. The lens didn't arrive for weeks and he started worrying whether it was lost on the way. He then was summoned by the customs authority to make a statement on the radioactive materia…
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That shouldn't change anything: https://en.wikipedia.org/wiki/Fair_coin#Fair_results_from_a_...
That argument relies on independent samples, but if someone's beaming radiation at the device to control its output, the samples will not be independent.
The closest you can get is bring it closer/further, or shield/unshield.
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That argument relies on independent samples, but if someone's beaming radiation at the device to control its output, the samples will not be independent.
It's not that easy to control radiation, controlling it to the level of individual decays is not possible. The closest you can get is bring it closer/further, or shield/unshield.
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My device, as other implementation, use the particle passing through the Geiger tube as a "virtual coin" , given a sampling frequency, if one or more particles are detected the firmware returns 1, if no particle is detected, zero. In other words, the random numbers are built a bit at time. My configuration with the background radiation returns too many zeros, so I needed something more ... lively. Anyway, what is the…
John Von Neumann’s method of creating a uniform distribution of random numbers from a skewed source (too many zeros) was: “(From a stream of) bits, (take) two at a time (first and second, then third and fourth, and so on). If the two bits matched, no output was generated. If the bits differed, the value of the first bit was output … (this) can be shown to produce a uniform output even if the distribution of input bit…
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My device, as other implementation, use the particle passing through the Geiger tube as a "virtual coin" , given a sampling frequency, if one or more particles are detected the firmware returns 1, if no particle is detected, zero. In other words, the random numbers are built a bit at time. My configuration with the background radiation returns too many zeros, so I needed something more ... lively. Anyway, what is the…
I have serious concerns about purchasing one and being put on "a list". But this city is lackadaisical at best when it comes to industry. And we've had incidents where radioactive materials have been found in construction near homes. So IDK. I feel like I probably should have one.
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Couldn't you just measure background radiation?
Would that be cryptographically secure? Couldn't someone perturb an RNG based on background radiation by beaming radiation at it?