And we do care about planets like the Earth because by now we understood that life as a chemical system really needs a smaller planet with water and with rocks and with a lot of complex chemistry to originate, to emerge, to survive.
而我们关心的正是这个问题 因为我们知道 生命这样精密的化学反应系统 只能存在于较小的行星上 需要有水，有岩石 需要很多复杂的化学过程 生命才得以起源，成形，以及生存下去