4 ms·
It's U-238, so the half-life is about 4.6 Billion years. Not totally stable, but pretty damn stable.
by AlgorithmicTime 5y ago
It's U-238, so the half-life is about 4.6 Billion years. Not totally stable, but pretty damn stable.
- nsonha 5y agoI don't think stable refers to the half life. It's a binary status.
- Koshkin 5y agoGood 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!
- Symbiote 5y agoIf 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+238.05078826+-+6.02214076e23+%2F+238.05078826+*+2%5E%28-1%2F1.4099635e17%29 https://www.wolframalpha.com/input/?i=6.02214076e23+%2F+238....
- ars 5y agoThat'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.