an edge to有一道到此为止的边

I was in a television studio when the Apollo mission launched. It was the first time that any human had moved away far enough from the earth to see the whole planet. And this is what they saw... what we all saw. Our planet, vulnerable and isolated. One of the extraordinary things about it was that the world could actually watch it as it happened. It was extraordinary that you could see what a man out in space could see as he saw it at the same time. And I remember very well that first shot. You saw a blue marble, a blue sphere in the blackness, and you realized that that was the earth. And in that one shot, there was the whole of humanity with nothing else except the person that was in the spacecraft taking that picture. And that completely changed the mindset of the population, the human population of the world. Our home was not limitless. There was an edge to our existence. It was a rediscovery of a fundamental truth. We are ultimately bound by and reliant upon the finite natural world about us. This truth defined the life we led in our pre-history, the time before farming and civilization.

阿波罗任务发射的时候，我正在电视演播室里。 这是人类第一次飞得离地球够远，远到能看见整个星球。 而这，就是他们看见的…… 也是我们所有人看见的。 我们的星球，脆弱，又孤零零的。 这件事了不起的地方之一，是全世界居然能在发生的同时亲眼看着。 你能在同一时刻，看见太空中那个人正在看见的一切，这太不可思议了。 那第一个镜头，我记得清清楚楚。 你看见一颗蓝色的弹珠， 漆黑之中的一颗蓝色球体，你这才意识到，那就是地球。 就在那一个镜头里，是全人类， 除此之外什么都没有，只有飞船里那个拍下照片的人。 这一点，彻底改变了地球上全体人类的心态。 我们的家园，并不是无边无际的。 我们的存在，是有边界的。 这是重新发现了一条根本的真理。 说到底，我们既受限于身边这个有限的自然世界，也依赖着它。 这条真理，决定了我们史前的生活，也就是农耕和文明出现之前的那段日子。