Island of stability (nuclear theory).
documentedphysical_evidenceLazar / S-4 / Exotic Tech
Real nuclear-physics prediction of longer-lived superheavy isotopes near Z~114-126, N~184. Provides theoretical hook for 'stable 115' speculation, but no stable Mc isotope has been produced.
Mainstream nuclear theory predicts an 'island of stability' around proton numbers ~114-126 and neutron number ~184 where enhanced shell binding could yield isotopes lasting far longer than current superheavies. This is genuine physics and is sometimes cited to keep 'stable element 115' speculation alive. However, no stable or long-lived moscovium isotope has ever been synthesized; the island remains theoretical for Z=115.