An astronomer at Harvard College, Henrietta Leavitt, had discovered that these periods of brightness could be used to measure the star's distance from Earth.

VOA: special.2009.04.29

In the case of the ambulance and police car, it's more a question of brightness.

警车和救护车上之所以用红灯，大多是因为红灯亮度大。

耶鲁公开课 - 文学理论导论课程节选

You can--Degrees of pushing, degrees of heat, degrees of brightness.

你能够感受到按压的程度,受热的程度,明亮的程度

耶鲁公开课 - 心理学导论课程节选

Its reddish color and changes in brightness over time make the planet an unforgettable sight.

VOA: special.2010.07.28

Visitors can enjoy the brightness and color of the universe she created.

VOA: special.2010.04.14