Europa is the smallest of planet Jupiter’s four largest moons and the second moon out from Jupiter. Until 1979, it was just another astronomy textbook statistiC.Then came the close-up images obtained by the exploratory spacecraft Voyager 2, and within days, Europa was transformed—in our perception, at least—into one of the solar system’s most intriguing worlds. The biggest initial surprise was the almost total lack of detail, especially from far away. Even at close range, the only visible features are thin, kinked brown lines resembling cracks in an eggshell. And this analogy is not far off the mark.
The surface of Europa is almost pure water ice, but a nearly complete absence of craters indicates that Europa’s surface ice resembles Earth’s Antarctic ice cap. The eggshell analogy may be quite accurate since the ice could be as little as a few kilometers thick—a true shell around what is likely a subsurface liquid ocean that, in turn, encases a rocky core. The interior of Europa has been kept warm over the eons by tidal forces generated by the varying gravitational tugs of the other big moons as they wheel around Jupiter. The tides on Europa pull and relax in an endless cycle. The resulting internal heat keeps what would otherwise be ice melted almost to the surface. The crack like marks on Europa’s icy face appears to be fractures where water or slush oozes from below.
Soon after Voyager 2’s encounter with Jupiter in 1979, when the best images of Europa were obtained, researchers advanced the startling idea that Europa’s subsurface ocean might harbor life. Life processes could have begun when Jupiter was releasing a vast store of internal heat. Jupiter's early heat was produced by the compression of the material forming the giant planet. Just as the Sun is far less radiant today than the primal Sun, so the internal heat generated by Jupiter is minor compared to its former intensity. During this warm phase, some 4.6 billion years ago, Europa’s ocean may have been liquid right to the surface, making it a crucible for life.
1. What does the passage mainly discuss?
2. It can be inferred from the passage that astronomy textbooks prior to 1979 _____.
3. It can be inferred from the passage that Europa and Antarctica have in common which of the following?
4. According to the passage, what is the effect of Jupiter's other large moons on Europa?
5. According to the passage, Voyager 2’s images led researchers to develop which of the following theories?
问题1选项
A.The effect of the tides on Europa’s interior
B.Temperature variations on Jupiter’s moons
C.Discoveries leading to a theory about one of Jupiter’s moons
D.Techniques used by Voyager 2 to obtain close-up images
问题2选项
A.provided many contradictory statistics about Europa
B.considered Europa the most important of Jupiter's moons
C.did not emphasize Europa because little information of interest was available
D.did not mention Europa because it had not yet been discovered
问题3选项
A.Both may have water beneath a thin, hard surface
B.Both appear to have a surface with many craters
C.Both have an ice cap that is melting rapidly
D.Both have areas encased by a rocky exterior
问题4选项
A.They prevent tides that could damage Europa’s surface
B.They prevent Europa’s subsurface waters from freezing
C.They produce the very hard layer of ice that characterizes Europa
D.They assure that the gravitational pull on Europa is maintained at a steady level
问题5选项
A.Jupiter may be hotter today than it once was
B.Europa is far older than scientists originally thought
C.Europa’s temperature is maintained by Jupiter’s vast store of internal heat
D.The ocean waters of Europa could contain some forms of life
第1题:C
第2题:C
第3题:A
第4题:B
第5题:D
1.主旨大意题。本文主要说明了一些关于木卫二的理论,因此C选项“这些发现导致了关于木星一颗卫星的理论”正确。A选项“潮汐对木卫二内部的影响”,B选项“木星卫星上的温度变化”,D选项“旅行者2号用来获得特写图像的技术”对应的都是文章中的一段,不全面。
2.推理判断题。由题干可以定位到文章第一段中“Europa is the smallest of planet Jupiter’s four largest moons and the second moon out from Jupiter. Until 1979, it was just another astronomy textbook statistic.”,中文翻译为:木卫二是木星四个最大的卫星中最小的,也是木星的第二个卫星。直到1979年,这只是天文学教科书上的数据。知C选项“没有强调木卫二是因为没有什么有趣的信息”正确。
3.细节事实题。由题干可以定位到文章第二段“The surface of Europa is almost pure water ice, but a nearly complete absence of craters indicates that Europa’s surface ice resembles Earth’s Antarctic ice cap. The eggshell analogy may be quite accurate since the ice could be as little as a few kilometers thick—a true shell around what is likely a subsurface liquid ocean that, in turn, encases a rocky core.”,中文翻译为:木卫二的表面几乎是纯净的水冰,但几乎完全没有陨石坑,这表明木卫二的表面冰类似于地球的南极冰盖。蛋壳的类比可能相当准确,因为冰层可能只有几公里厚——一个真正的外壳,围绕着一个可能是地下液态海洋的地方,而这个海洋反过来又包裹着一个岩石核心。因此,A选项“两者在薄而坚硬的表面下都可能有水”正确。
4.推理判断题。根据题干定位到原文第二段“The resulting internal heat keeps what would otherwise be ice melted almost to the surface. The crack like marks on Europa’s icy face appears to be fractures where water or slush oozes from below.”,中文翻译为:由此产生的内部热量使原本可能是冰的东西几乎融化到表面。在木卫二冰冷的表面上有类似裂缝的痕迹,似乎是水或泥浆从下面渗出的裂缝。故B选项“它们可以防止木卫二的地下水结冰。”最符合题意。
5.推理判断题。根据题干可以定位尾段“Soon after Voyager 2’s encounter with Jupiter in 1979, when the best images of Europa were obtained, researchers advanced the startling idea that Europa’s subsurface ocean might harbor life.”,中文翻译为:1979年,“旅行者2号”与木星相遇,获得了木卫二的最佳图像,之后不久,研究人员提出了一个令人吃惊的想法,即木卫二的地下海洋可能孕育着生命。可以得知D选项“木卫二的海水可能含有某种生命形式。”正确。