Feynmanium, refers to the hypothetical element with atomic number 137 (temporary name Untriseptium, Uts), named after Richard Feynman because he pointed out that a simple relativistic model suggested its 1s electrons would need to exceed the speed of light, implying the periodic table’s breakdown around this point; though modern theory places the limit much higher (around Z=173), it highlights the mysterious fine-structure constant (1/137) connecting quantum mechanics and relativity.