这个问题是由美国宇航局所提出的另一个问题引起的。美国宇航局在执行行星登陆计划之前,希望科学家予计一下在某一行星上到底有没有生命。答案自然是各色各样的,问题在于没有一个客观标准来衡量生命是否存在。化学家J.E.Lovelock提出了一个新判据。他说生物能够通过利用大气而把大气的组成推向远离平衡的稳态。他指出地球大气是一个高度活泼的气体混合物,它远未 This problem is caused by another issue put forward by NASA. Before implementing NASA’s NASA program, NASA hopes scientists will count whether there is any life on a particular planet. The answer is naturally varied, the problem is that there is no objective standard to measure the existence of life. Chemist J. E. Lowvel proposed a new criterion. He says creatures can push the composition of the atmosphere away from equilibrium by using the atmosphere. He pointed out that the earth’s atmosphere is a highly active gas mixture, far away