|
In physics, a gravitational coupling constant is a constant characterizing the gravitational attraction between a given pair of elementary particles. The electron mass is typically used, and the associated constant typically denoted ''α''G. It is a dimensionless quantity, with the result that its numerical value does not vary with the choice of units of measurement, only with the choice of particle. ==Definition== ''α''G is typically defined in terms of the gravitational attraction between pair of electrons. More precisely, : where: * ''G'' is the gravitational constant; * ''m''e is the electron rest mass; * ''c'' is the speed of light in vacuum; * ''ħ'' ("h-bar") is the reduced Planck constant; * ''m''P is the Planck mass. In natural units, where , the expression becomes . This shows that the gravitational coupling constant can be thought of as the analogue of the fine-structure constant; while the fine-structure constant measures the electromagnetic repulsion between two particles with equal charge, the magnitude of which is equal to the elementary charge, this gravitational coupling constant measures the gravitational attraction between two electrons. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「gravitational coupling constant」の詳細全文を読む スポンサード リンク
|