The first approach is the “space elevator” concept, a favorite of science fiction authors. The idea is that we connect a tether to a satellite orbiting far enough out that the tether is held taut by centrifugal force. Then we can send climbers up the rope using ordinary electricity and motors, powered by solar power, nuclear generators, or whatever works best. The biggest engineering hurdle is that the tether would have to be several times stronger than anything we can currently build. There are hopes that carbon nanotube-based materials could provide the required strength-adding this to the long list of engineering problems that can be waved away by tacking on the prefix “nano-.”
第一个方法就是“太空电梯”设想，它是科幻作家的最爱。这个方法其实就是绑一条绳索在围绕地球飞行的卫星上，这颗卫星的距离远到离心力能够把这根绳索拉紧。然后我们就可以用平常的太阳能或核电站，或随便什么好用的方法驱动电机，来把我们沿着绳索送上太空了。这个方案最大的工程难题在于，这根绳索所需要的强度是我们能够建造出来的最坚韧的材料的强度的好几倍。有人希望碳纳米管能够满足所需要的强度，于是“祭出‘纳米’这个前缀就可以轻松解决的工程难题”的长长名单上，又多了一个名字。
The second approach is nuclear pulse propulsion, a surprisingly plausible method for getting huge amounts of material moving really fast. The basic idea is that you toss a nuclear bomb behind you and ride the shockwave. You'd think the spacecraft would be vaporized, but it turns out that if it has a well-designed shield, the blast would fling away before it has a chance to disintegrate. If it could be made reliable enough, this system would in theory be capable of lifting entire city blocks into orbit, and could-potentially-accomplish our goal.
第二种方法就是核脉冲推进，这种方法能将极大质量的物体加速到很高的速度。它的基本原理就是你不停地往外扔核弹，然后借助核爆的冲击波前进。你可能觉得核爆会摧毁飞船，但事实是如果你能装备一个精心设计的护盾，在护盾解体前冲击波早就消散掉了。如果这套系统足够可靠，那么理论上它能把一整个街区送上太空，这样离实现我们那个伟大目标也就不远了。
The engineering principles behind this were thought to be solid enough that in the 1960s, under the guidance of Freeman Dyson, the US government actually tried to build one of these spaceships. The story of that effort, dubbed Project Orion, is detailed in the excellent book of the same name by Freeman's son, George. Advocates for nuclear pulse propulsion are still disappointed that the project was cancelled before any prototypes were built. Others argue that when you think about what they were trying to do-put a gigantic nuclear arsenal in a box, hurl it high into the atmosphere, and bomb it repeatedly-it's terrifying that it got as far as it did.
这个方案背后的工程原理在20世纪60年代就已经被认定是非常健全的了，在弗里曼•戴森的指导下，美国政府曾一度想要造出这样的飞船。这个项目被称为“猎户座计划”，弗里曼的儿子乔治写的一本很棒的同名书里详细地介绍了这个项目。后来这个项目连一个原型机都没造出来就被取消了，核脉冲推进的支持者们至今仍然对此耿耿于怀。但其他人则认为当想象一下他们要做的事情——在一个盒子里装上大量核武器，把它抛到空中，然后不停地引爆核弹——这个项目居然还有目前的进展就已经让人匪夷所思了。
So the answer is that while sending one person into space is easy, getting all of us there would tax our resources to the limit and possibly destroy the planet. It's a small step for a man, but a giant leap for mankind.
所以答案是只把一个人送上太空是非常容易的事情，但要把所有人类都送入太空则会将我们的各种资源都推向极限，甚至还有可能毁掉整个地球。这时就真的是“一个人的一小步，全人类的一大步”了。
1 There are probably around a million tons of pet dog in the US alone.
1． 单美国宠物狗的重量就有大约1亿吨。
Q. In Thor the main character is at one point spinning his hammer so fast that he creates a strong tornado. Would this be possible in real life?
Q．在电影《雷神》中，男主人公曾把他手中的锤子转得飞快，以至于产生了强大的龙卷风。这在现实中是可能的吗？
Q. If you saved a whole life's worth of kissing and used all that suction power on one single kiss, how much suction force would that single kiss have?
Q．如果你把一辈子亲吻的力气都省下来，并且都用到一次亲吻上，那么你能产生多大的吸力？
Q. How many nuclear missiles would have to be launched at the United States to turn it into a complete wasteland?
Q．需要多少射向美国的核导弹才能把美国彻底夷为平地？