(九下)Unit 4 Life on Mars
A
电影《流浪地球Ⅱ》中的通往太空的电梯给人们带来了许多遐想。人类真的可以搭建出一个通向太空的电梯吗？
The science fiction movie The Wandering Earth Ⅱ has been a hit since its release. The space elevators in the movie are quite impressive—elevator cars travel quickly between the cables that connect Earth's surface and the space station. This device may not only be entirely fictional in the future.
Early in 1895, Russian scientist Konstantin Tsiolkovsky was inspired by the Eiffel Tower. He pointed out that if humans could build a tower high enough to reach space, people would be able to travel by space elevators. However, such a tower is impossible because no matter how large the base is, it would not be able to support the whole system.
Scientists thus considered the idea in a different way. There are satellites in Earth's orbit which is about 36,000 kilometres in altitude. They appear to be fixed in space and rotate around Earth once per day because their speed is just right. According to Scientific American, scientists argued that if such a satellite were to drop cables towards Earth which were then fixed to its surface, the whole system would rotate along with the planet. The elevator could then travel through the tracks.
Now that the theory is sound, one of the challenges that stop engineers from building the elevators is the cables' material. According to an article by the Institute of Physics Chinese Academy of Sciences, a carbon nanotube made of carbon atoms might be the most viable material. A short tube that weighs 1.6 grams can hold more than 800 tons which is about the weight of 160 elephants. Since its discovery in 1991, scientists have been trying to create a tube that is as long as possible. However, the longest tube with a perfect structure was only about half a metre, developed by a team at Tsinghua University in 2013.
Why go through so much trouble? The benefits of space elevators are clear. For example, elevators require far less energy and money than rockets, currently the main transportation to space. Also, with space elevators, space missions would be more frequent—even become a routine.
WORD BOX ＞＞
| release | [rɪ'liːs] | n. 发行 | cable | ['keɪbl] | n. 电缆 |
| altitude | ['æltɪtjuːd] | n. 海拔 | rotate | [rəʊ'teɪt] | vi. 旋转 |
| atom | ['ætəm] | n. 原子 | viable | ['vaɪəbl] | adj. 可实施的 |
| currently | ['kʌrəntli] | adv. 当前 | | | |
COMPREHENSION CHECK UP ＞＞
Ⅰ. Match each word in the passage with the correct meaning.
1. device
a
2. entirely
f
3. theory
e
4. require
d
5. mission
c
6. frequent
b
Ⅱ. Tell whether the following sentences are true (T) or false (F).
(
T
) 1. People show great interest in the elevators in The Wandering Earth Ⅱ.
(
F
) 2. An American scientist thought people could travel to space by elevator.
(
T
) 3. Scientists suggested building an elevator between a satellite and Earth.
(
T
) 4. Chinese scientists invented the longest tube with a perfect structure.
(
F
) 5. Using elevators will cost more money than travelling by rockets.
Ⅲ. Answer the following questions.
1. Why is the movie The Wandering Earth Ⅱ mentioned in paragraph 1?
To introduce the topic of space elevators.
2. What does the underlined phrase "the idea" in paragraph 3 refer to?
Building a tower high enough to reach space for space elevators.
3. What is paragraph 4 mainly about?
The challenge of the cables' material for building space elevators.
