#託福奇葩背景知識系列#
託福聽力裡面有很多讓人覺得難以理解的內容，其實回顧內容的時候會發現並不難，只是聽的時候由於缺乏相關背景知識，讓我們的推導能力受到了限制。所以，我們推出了【託福奇葩背景知識系列】，不僅漲分數，還漲姿勢哦！
聽說你，想上天，想跟太陽肩並肩？
太陽就算了，會被燒死的。
我們還是跟地球一起肩並肩，繞著太陽轉圈圈吧。
那，怎麼跟地球肩並肩呢？
首先，來認識一下 Geostationary Orbit。
Geostationary orbit, a circular orbit 35,785 km (22,236 miles) above Earth’s Equator in which a satellite’s orbital period is equal to Earth’s rotation period of 23 hours and 56 minutes. A spacecraft in this orbit appears to an observer on Earth to be stationary in the sky. This particular orbit is used for meteorological and communications satellites. The geostationary orbit is a special case of the geosynchronous orbit, which is any orbit with a period equal to Earth’s rotation period.
The concept for such an orbit was proposed in 1945 by British author and scientist Arthur C. Clarke in an article entitled 「Extra-Terrestrial Relays」 for Wireless World. The article envisioned the current communications satellite system that relays radio and television signals throughout the world. The U.S. communications satellite Syncom 3, which was launched on Aug. 19, 1964, was the first object to be placed in geostationary orbit.
記住這個數值：35,785km
把衛星發送到這兒，就可以跟地球同步運轉了。
還有這位大佬：Arthur C. Clarke
1945年阿瑟大佬就提出了這個概念，然而當時所有人都以為他是個異想天開的科幻小說家。難怪說真理總是在少數人手裡。
第二步，讓衛星上的萵苣姑娘把頭髮放下來，讓你爬上去。
開玩笑，咳咳。
「頭髮」肯定是要有講究的，這個時候就要用到我們曾經熟知的
Nanotechnology 納米科技 （其實我只在廣告裡聽說過納米牙刷，嘻嘻）
需要用來做吊索的材料叫碳納米管，carbon nanotubes。其強大的特質，讓它成為能輔助我們爬上天的不二人選。
Carbon nanotubes were discovered in 1991. Where buckyballs are round, nanotubes are cylinders that haven’t folded around to create a sphere. Carbon nanotubes are composed of carbon atoms linked in hexagonal shapes, with each carbon atom covalently bonded to three other carbon atoms. Carbon nanotubes have diameters as small as 1 nm and lengths up to several centimeters. Although, like buckyballs, carbon nanotubes are strong, they are not brittle. They can be bent, and when released, they will spring back to their original shape.
The properties of nanotubes have caused researchers and companies to consider using them in several fields. For example, because carbon nanotubes have the highest strength-to-weight ratio of any known material, researchers at NASA are combining carbon nanotubes with other materials into composites that can be used to build lightweight spacecraft.
（Excerpted from Nanotechnology For Dummies (2nd edition), from Wiley Publishing）
OK了，坐穩扶好，carbon nanotubes準備拉你上天。
打開TPO，聽ETS給你講晚安故事
TPO29 Lecture4 Carbon Nanotubes
重點詞彙：
obstacle 阻礙，障礙
space shuttle 太空梭（往返於地球和太空站之間運載人和物資的）
escape velocity 逃逸速度（擺脫星球引力束縛的最低速度）
misconception 錯誤觀念
solar energy 太陽能
feasible 可行的
theoretically 理論上地
tensile strength 抗拉強度
molecular level 分子級
tether 拴繩