Because positing them allows you explain things about the rotation of the star or the gravitational fluctuations, what have you.

因为这样假定能帮助你解释,诸如星体运行,引力波动,等现象

耶鲁公开课 - 死亡课程节选

There is no star where the Morning Star had been or where people have claimed it would be or something.

一颗星也没有,无论是晨星曾经出现的地方或,是人们曾断言晨星会出现的地方

耶鲁公开课 - 死亡课程节选

There are lots of people using Star Festival all through United States or even abroad.

美国各地甚至国外,有很多人在参与“七夕“项目。

麻省理工公开课 - 媒体、教育、市场课程节选

So we're going to call this the sigma 2 p x star, or if we're talking about the 2 p y orbitals we'll call this the pi 2 p x star, and the pi 2 p y star.

我们叫这个sigma2px星，或者如果我们说的是π2py轨道的话,我们叫这个2px星，这个π2py星。

麻省理工公开课 - 化学原理课程节选

So when I refer to the Morning Star, I'm talking about Venus, whether or not I realize it's Venus.

所以说,当我谈到晨星的时候,我就是在指金星,不管怎么样,我认为那是金星

耶鲁公开课 - 死亡课程节选

When I talk about the Evening Star, I'm referring to Venus, whether or not I realize that Venus is the Evening Star.

当我说到昏星的时候,我指的也是金星,不管怎么样,我认为,金星就是昏星

耶鲁公开课 - 死亡课程节选