fine-structure constant

noun

(electrodynamics) The fundamental physical value α, presumed to be constant, that characterizes the strength of the electromagnetic force.

The fine-structure constant is a fundamental constant in physics.

意味（1）

(electrodynamics) The fundamental physical value α, presumed to be constant, that characterizes the strength of the electromagnetic force.

意味（2）

(in our Universe) a value of approximately 1/137 = 0.0072973525