Limits RegistryPUBLIC RECORD
Limits RegistryLead (Z = 82) is the heaviest element with stable isotopes; lead-208 is doubly magic. Bismuth (Z = 83) was long considered stable until a team at the Institut d'Astrophysique Spatiale in Orsay, France, detected alpha decay of bismuth-209 in 2003, with a half-life of about 1.9 × 10^19 years — over a billion times the age of the universe.
The question, scope, and sources behind this Registry record.
Lead (Z = 82) is the heaviest element with stable isotopes; lead-208 is doubly magic. Bismuth (Z = 83) was long considered stable until a team at the Institut d'Astrophysique Spatiale in Orsay, France, detected alpha decay of bismuth-209 in 2003, with a half-life of about 1.9 × 10^19 years — over a billion times the age of the universe.
The highest atomic number of any element with at least one isotope that has never been observed to decay.
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Current frontiers derived from accepted Claims.
An observed or demonstrated result; no opposing bound is implied.
The frontier is not sacred
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≥ when you have shown that at least this value is achievable.≤ when you have shown that anything above this value is impossible.No vibes. State the value, define the scope, and link the paper, proof, code, or reproduction that lets another person check it. Editors review every challenge before the public record changes.
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The frontier as it changed over time.
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1 accepted Claim, with 1 linked evidence records.
Permanent ID limitsregistry.com/limits/LR-HEAVIEST-ELEMENT-WITH-STABLE-ISOTOPE
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Limits Registry. LR-HEAVIEST-ELEMENT-WITH-STABLE-ISOTOPE. Heaviest element with a stable isotope. 2026.