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[-] quediuspayu@lemmy.dbzer0.com 53 points 1 month ago

Put that chunk of uranium on a scale and you have a 700 milion year calendar

[-] slaneesh_is_right@lemmy.org 24 points 1 month ago

Thanks but i find an annual calendar already pretty overwhelming

[-] hperrin@lemmy.ca 38 points 1 month ago

GOD DAMNIT! Who touched my Uranium-235?? I left it RIGHT HERE where this lead is.

[-] SaharaMaleikuhm@feddit.org 6 points 1 month ago

Just eat the lead to make all the worries disappear

[-] xx3rawr@sh.itjust.works 5 points 1 month ago

Somebody touch-a my U235

Whose responsible this?!?!

[-] skisnow@lemmy.ca 31 points 1 month ago

Who measures uranium in pounds? I feel like if you're not using metric you probably shouldn't be handling uranium.

[-] Iron_Lynx@lemmy.world 30 points 1 month ago

So I ran the numbers. U-235 decays into Pb-207, which means about 12% of its mass is radiated away in alpha decay. Which sounds like a fuckton.

Also, it'll mean that that chunk of lead will be a touch heavier, at 13.2 lbs

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.

[-] sga@piefed.social 8 points 1 month ago

also, uranium's half life is 700 million years, so we expect (207/235)*7.5 (of lead) + 7.5 (uranium) ~ 14.106382978723405 lump.

also, a lot of the helium produced will remain trapped inside (most heavy metal lumps act as sponges for little gasses). but 700 mil years is also a large amount of time, so much of it would diffuse out. I could checkup diffusion statistics for he d pb-u but i would have to probably do a double integral (as pb-u combination is not fixed, and we can not simply do the error function calculation), so skipping that. but it is safe to say that we will have a lump of ~50% U, 44% pb, and 6% He (by mass), and a significant amount of he will remain in

[-] Iron_Lynx@lemmy.world 2 points 1 month ago

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

[-] notabot@piefed.social 29 points 1 month ago

Woahhh. That's heavy maaannn.

[-] cryoistalline@lemmy.ml 16 points 1 month ago

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

[-] Zuriz@sh.itjust.works 2 points 1 month ago

1 hour here is 7 years on earth .jpg

[-] ChicoSuave@lemmy.world 5 points 1 month ago

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

[-] psud@aussie.zone 1 points 1 month ago

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

[-] Maroon@lemmy.world 5 points 1 month ago

No snoot, there'd be crabs!!

This meme is false.

[-] jawa22 5 points 1 month ago* (last edited 1 month ago)

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 points 1 month ago
[-] jawa22 1 points 1 month ago

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 points 1 month ago

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

[-] klemptor@startrek.website 4 points 1 month ago

Awww greyhound snoot ๐Ÿ˜

this post was submitted on 14 Sep 2025
661 points (100.0% liked)

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