::: spoiler The Maths: U-235 decays into Pb-207. To three significant digits, 207/235 = 0.881, equivalent to 88.1%, meaning 11.9% is radiated away.
88.1% of 15 lbs = 13.2 lbs. :::

ryannathans@aussie.zone · 13 pts · 358d

And that's ignoring spontaneous fission which is probably happening to some extent to some of the isotopes

sga@piefed.social · 9 pts · 357d (1 reply)

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Iron_Lynx@lemmy.world · 2 pts · 357d

So it would be more accurate to say that 13.2 lbs would be a minimum for the lump's mass.

cryoistalline@lemmy.ml · 16 pts · 358d (1 reply)

u-235 has a half life of 704 million years. only half of it would have decayed.

Zuriz@sh.itjust.works · 2 pts · 357d

1 hour here is 7 years on earth .jpg

Maroon@lemmy.world · 6 pts · 357d

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ChicoSuave@lemmy.world · 5 pts · 358d (1 reply)

So a chunk of lead today could have been pre-cambrian uranium?

psud@aussie.zone · 1 pts · 354d

A little older, with a ~700 million year half life and about ten half lives to be practically completely converted you're looking for 7 billion years ago

jawa22@lemmy.blahaj.zone · 5 pts · 358d (3 replies)

Reminds me of my ingot of invar. Every few years I try to think of something to do with it, but still haven't come up with anything.

zorblitz@mander.xyz · 2 pts · 356d (2 replies)

What's invar?

jawa22@lemmy.blahaj.zone · 1 pts · 356d (1 reply)

https://en.m.wikipedia.org/wiki/Invar

In short, it is an alloy that experiences almost zero thermal expansion or contraction.

zorblitz@mander.xyz · 1 pts · 355d

And I thought it was some deez nuts joke that I wasn't aware of

klemptor@startrek.website · 3 pts · 357d

Awww greyhound snoot 😍

guthibnet@lemmings.world · -1 pts · 357d

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