单词solar day
na.: 太阳日
太阳日
a solar day is the length of time it takes the Earth to revolve once around the sun.
一个太阳日是地球长度围绕太阳一圈的时间。
In terms of how we keep track of time, it is easiest to go by the solar day and the tropical year.
说到我们怎么计算时间，最简单的方法使用太阳日和回归年。
The biological clock is probably the result of human evolutionary adaptation to the solar day.
生物钟可能是人类为了适应太阳日而进化的结果
So, if we call a solar day 24 hours, then how many of these days fit into a year?
所以，如果我们把一个太阳日定义为24小时，那么一年会有多少天？
The problem with the solar day is that it doesn"t really tell you how fast the Earth spins. Why?
太阳日的问题在于它并没有告诉你地球的自转速度。为什么？
this is exactly how the sundial works . this defines the solar day.
利用太阳投影位置量度时间的日晷，便是根据这个定义运作的计时仪器。
Here is the key point: the solar day and the tropical year aren"t locked in anyway.
关键在于：太阳日和回归年相互并无关联。
A sidereal day is about 4 minutes shorter than a solar day .
一个恒星日比一个太阳日大约短4分钟。
is shorter than a mean solar day by 3 minutes and 56 seconds.
恒星日比平均太阳日短三分五十六秒。
they tracked natural cycles : the solar day , the lunar month and the solar year
他们遵循自然的循环：太阳日、太阴月，还有太阳年。