任何系统的能量最终都来源于太阳，并以某种形式返回到宇宙中。

The present state of the system of nature is evidently a resultant of what it was in the preceding moment, and if we conceive of an intelligence which at a given instant comprehends all the relations of the entities of this universe, it could state the respective positions, motions, and general effects of all these entities at any time in the past or future.

We don't ever let go of anything, we just go on to the next thing.

时间不是线性的；它是一个循环。