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Comment by tokai | Hacker News Reader

No its uranium.

Is this glass dangerous then?

> ... can register above background radiation on a sufficiently sensitive Geiger counter, although most pieces of uranium glass are considered to be harmless and only negligibly radioactive.

Missed that. Thanks.

The food you eat every day is much more dangerous than Uranium glass, unless you also eat Uranium glass.

Uranium, like lead, mercury, cadmium, arsenic, is a heavy metal and toxic, separate from any radiation, although the alpha particles from U-238 are only dangerous if ingested or inhaled, anyway.

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.

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!

If I remember this correctly...

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)

will decay. Double precision arithmetic isn't enough for this (though it is for 1 day), but Wolfram's calculator works: 12,436 atoms decay.

https://www.wolframalpha.com/input/?i=6.02214076e23+%2F+238....

That's true, sort of. Some elements can have such long half lives they are effectively stable, and can be treated as if they are. For example tellurium 123, 128, and 130; and Bismuth 209.

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