The important thing here to note is that in the meantime, the four and a half billion years, these comets have been sitting on the outside of the solar system, and haven't changed -- deep, frozen versions of our solar system.
需要注意的重点是，在此期间， 这45亿年间， 这些彗星一直安坐在太阳系之外， 并且从没变过—— 深沉、冻结版的太阳系。