Lecture 1 走向太空
Wors Tips
radically adv.根本地；彻底地 obstacle n.障碍；障碍物
spaceshuttle 航天飞机 enormous adj.巨大的
misconception n.错误认识；误解 velocity n.速度
haulup 拖上去，拉上去 fraction n.小部分；少量
feasible adj.可行的 lightweight adj.轻量的，薄型的
tensile adj.张力的；拉力的 nanotube n.纳米管
ribbon n.丝带；带子
Listen to the following recording and answer questions 1-4.
1）A.It’s too costly.
B.The current technology is unable to do it.
C.It’s prohibited by laws.
D.It’s feared that there might be aliens.
2）A.to demonstrate his familiarity with certain new types of technology
B.to make sure he understands the point the professor is making
C.to raise an objection to the professor’s claims about escape velocity
D.to provide a humorous example for the other students’ amusement
3）A.to build a tall tower
B.to build a huge rocket
C.to build a long ladder
D.to build an elevator
4）A.fragile and hard
B.heavy and soft
C.strong and flexible
D.fragile and light
听力原文
Professor：Today let’s begin to look at structural engineering in the Space Age.Uh，new problem，new possibilities mean we can think in new ways，find radically different approaches.So let’s consider，uh，well，what would you say is the biggest obstacle today to putting structures，equipment，people，uh，anything really，into space？
Student：Well，the cost，right？
Professor：Exactly.I mean，just taking the space shuttle up and back one time is hugely expensive.We are burning up an enormous amount of fuel at every launch just to get the rocket up to what’s known as escape velocity.Now，escape velocity is around 11 kilometers a second，pretty fast.But do we really have to go this fast？ Actually，that’s a common misconception.Escape velocity is simply the speed of an object that’s，uh，let’s say，shot out of a cannon the minimum initial speed so that the object could later escape Earth’s gravity on its own.But that’s just if there’s no additional force being applied.If you keep on supplying force to the object，keep on pushing it upward.It could pull away from Earth’s gravity at any speed.
Student：Even really slow？ So you’re saying like，if you had a ladder tall enough，you could just climb into space？
Professor：Yeah！ Uh，well，theoretically.I mean，I can see some practical problems with the ladder example.Uh，like you might get just a little bit tired out after the first few thousand kilometers or so，uh，especially with all the oxygen tanks you’ll have to be hauling up with you.No.I was thinking more along the lines of an elevator.An elevator.That’s a new idea to most of us，but in fact it’s been around for over a century.If we could power such an elevator with solar energy，we could simply rise up into space for a fraction of the cost of a trip by rocket or shuttle.
Student：But wait，elevators don’t just rise up.It has to hang on some kind of wire or track or something.
Professor：Uh，true.And for decades that’s exactly what’s prevented the idea from being feasible or even just taken seriously.Where do we find the material strong enough yet lightweight enough to act as a cable or track？ I mean，we are talking 36，000 kilometers here.And the strain on the cable would be more than most materials could bear.But a new material developed recently has a tensile strength higher than diamond，yet it’s much more flexible.I am talking about carbon nanotubes.You pull out one nanotube or row of nanotubes，and its neighbors come with it，and their neighbors，and so on.So you could actually draw out a 36，000-kilometer strand or ribbon of nanotubes stronger than steel，but maybe a thousandth the thickness of a human hair.
Questions：
1.What is the biggest obstacle today to putting structures，equipment and people into space？
2.Why does the student mention climbing a ladder？
3.What new approach does the professor propose？
4.What features do the new material carbon nanotubes have？
参考译文
教授：今天我们来看看太空时代的结构工程学。新的问题、新的可能性意味着我们能够用新的方式思考，找到全新的方法。让我们来考虑一下，你觉得现今把构造、设备、人类运送到太空中面临的最大困难是什么？
学生：嗯，费用，对吧？
教授：没错。仅仅发射太空器到太空再把它们召回一次的费用就很高。每一次发射我们都会燃烧大量燃料以使火箭达到宇宙速度。宇宙速度大约是11千米每秒，非常快。但是我们真的需要达到这么快的速度吗？事实上，这是个非常普遍的误解。宇宙速度只是一个物体（比如一个从加农炮里射出的物体）要有的最小的能使它之后能靠自己摆脱地球引力的速度，但是这是仅指没有其他外力作用于这个物体的情况。如果你在发射过程中不断地对这个物体施加外力，不断地把它向前推，那不管它最初速度多大，最终它都有可能摆脱地球引力。
学生：就算初速度非常低也可以？这就好比如果你有个足够高的梯子，你就能沿着梯子爬到太空中？
教授：没错！理论上讲是这样。但是你的梯子例子面临着一些实际操作上的问题。比如你在爬了几千米之后会很累，尤其是当你还拖着一堆氧气瓶的时候。我觉得电梯更适合。电梯！对我们所有人来说这个想法可能很新鲜，但是其实一个世纪前就有人这么构想过了。如果我们能用太阳能对这样一个电梯供能，我们就能以用火箭或者飞行器的费用的几分之一的费用进入太空。
学生：但是，电梯不能仅靠自己上升。它需要在一个轨道上运作。
教授：没错。几十年来就是这个想法阻碍了电梯的发展，也阻碍了人们严肃地考虑它的可行性。我们到哪里去找这样一个能承重并且超轻的材料做电梯的轨道或者绳索呢？绳索足足有36000千米。这个绳索将承受极大的压力，大到大多数材料都不能承受。但是一种新开发的材料，它的抗张强度比钻石还高，而且柔韧度更好。它，就是碳纳米管。我们拔出一个或者一排纳米管，临近的纳米管便会自动聚合，一直延绵不断。所以，实际上你可以做一个比钢铁承重能力强，但只有头发千分之一细的36000千米长的纳米管。
参考答案
1.A 2.B 3.D 4.C