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submitted 2 months ago by fossilesque@mander.xyz to c/science_memes@mander.xyz

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[-] UnrepentantAlgebra@lemmy.world 103 points 2 months ago

I'll go down this rabbit hole for you because I was also curious.

https://www.scientificamerican.com/article/ancient-roman-lead-physics-archaeology-controversy/

All lead mined on Earth naturally contains some amount of the radioactive element uranium 235, which decays, over time, into another radioactive element, a version of lead called lead 210. When lead ore is first processed, it is purified and most of the uranium is removed. Whatever lead 210 is already present begins to break down, with half of it decaying on average every 22 years. In Roman lead almost all of the lead 210 has already decayed, whereas in lead mined today, it is just beginning to decay. (Of course, many lead 210 atoms have already decayed in this ore, too, but the supply is constantly replenished by uranium in unprocessed lead). "The longer since it was originally processed, the lower its intrinsic radioactivity," Gonzalez-Zalba says.

[-] fullsquare@awful.systems 8 points 2 months ago

they did a whoopsie, lead 210 comes from uranium 238. every 220 years radioactivity drops 1000x which means that 200-300 year old lead is mostly fine. copper notably doesn't have this problem, is dense and is refined to high degree, at scale. it's good enough to shield most of relatively low energy radiation from that isotope (less than 50kev gammas). couple mm of copper should be plenty for many applications

[-] unemployedclaquer@sopuli.xyz 5 points 2 months ago

You can still get Job in metal shop

[-] unemployedclaquer@sopuli.xyz 4 points 2 months ago

not all from me, but I recommend snacks

this post was submitted on 08 Apr 2026

546 points (100.0% liked)

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