由于地球自转速率发生偏离，因此当把地球绕中轴旋转一圈作为一个单位时，（这种偏离）就相当于一秒钟时间。

Since Earth’s rotation rate varies, so would the value of one second when it’s defined as a fraction of the time it takes for one spin of the Earth on its axis.

youdao

由于地球自转速率发生偏离，因此当把地球绕中轴旋转一圈作为一个单位时，（这种偏离）就相当于一秒钟时间。

Since Earth’s rotation rate varies, so would the value of one second when it’s defined as a fraction of the time it takes for one spin of the Earth on its axis.

youdao