Official 24 Set 6

纠错
  • Q1
  • Q2
  • Q3
  • Q4
  • Q5
  • Q6
置顶

Shield Volcanoes on Venus

纠错
  • Q1
  • Q2
  • Q3
  • Q4
  • Q5
  • Q6
What is the lecture mainly about?
  • A. Conclusions about the surface of Venus drawn from recent observations

  • B. The different types of volcanoes that have been found on Venus

  • C. Similarities between geologic processes on Venus and on other planets

  • D. New methods used to observe the surface of Venus

显示答案 正确答案: A

我的笔记 编辑笔记

/
  • 原文
  • 译文
  • 查看听力原文

    关闭显示原文

    NARRATOR:Listen to part of a lecture in an Astronomy class.

    MALE PROFESSOR:Uh, many people have been fascinated about Venus for centuries because of its thick cloud cover… the so-called “planet of mystery” and all of that.Well, what’s under those clouds? What’s the surface of the planet like?Uh, some questions about the surface are still unresolved, but…but we have learned a lot about it in the past several years.First of all, let me talk about how we’ve been able to get past those clouds.First there were Soviet modules that landed directly on the surface and sent back some images of what was around them.Second, we did some radar imaging from satellites from above. Radar can get through the clouds.[asking himself, not the class]So, what have we learned? Yes, Karen?

    FEMALE STUDENT:Well, I remember reading that there’s not really a lot going on… that the surface of Venus is just flat and smooth in a lot of places…

    MALE PROFESSOR:Uh, yeah, it’s smooth in a lot of places, but that’s not… uh, that’s not the whole picture.In other areas, you’ve got canyons, rift valleys, meteoric craters, uh,lava domes—these lava formations that look like giant pancakes—and also volcanoes… well, one of the most interesting features on the surface are, in fact, the shield volcanoes.

    Shield volcanoes form when magma comes out of the ground in the same spot over and over again.Remember, magma is hot, molten rock that’s underground and it’s called lava when it reaches the surface— uh, so the lava builds up and hardens, and a volcano forms.Now, the lava on Venus is thin. It spreads out easily. So shield volcanoes have very gentle, sloping sides.They’re called shield volcanoes because viewed from above, they kind of resemble shields, you know, like a warrior’s shield.

    But what’s particularly interesting about these volcanoes is that most of the volcanoes here on Earth are not shield volcanoes.Instead, they’re other volcano types, like stratovolcanoes for example, which are a result of tectonic plate movement.Remember tectonic plates?Underneath the Earth’s crust, there are a number of shifting slabs or plates that are slowly moving.And in the zones on the edges of the plates, where different plates meet and interact, that’s where we get most of Earth volcanoes.On Venus, however, volcanoes are not clustered in discrete zones like they’re on Earth.Instead, they’re more or less randomly scattered over Venus’ surface.Well, that’s significant: Venus has mostly shield volcanoes, and they’re randomly scattered— that indicates that Venus does not have moving tectonic plates, and that’s a big difference compared to Earth.Here on Earth, moving tectonic plates are a major geological element… just crucial for the whole surface dynamic, right?So why doesn’t Venus have them?Well, there are a few theories— uh, one of them is that this has to do with the fact that Venus has no surface water that’s needed to kinda lubricate the movement of the plates.You know, like oceans on Earth?Yeah, I forgot to spell that out, uh,Venus has no surface water…

    FEMALE STUDENT:Wait a second, did you say we have shield volcanoes on Earth? Can you give an example?

    MALE PROFESSOR:Sure… the volcanoes in the Hawaiian Islands, in the Pacific Ocean, are shield volcanoes; they’re formed over a hot spot of magma.So while on Earth we have several types of volcanoes, on Venus, there is mostly the one type.Uh, Eric?

    MALE STUDENT:Uh, are the volcanoes on Venus still active?

    MALE PROFESSOR:Well, that’s an interesting question. There’s still some discussion on that point. But here’s what we do know.First, the level of sulfur dioxide gas above Venus’ clouds shows large, and uh, very frequent fluctuations.It’s quite possible that these fluctuations, the huge increase and decrease of sulfur dioxide, happening again and again, it’s quite possible that this is due to volcanic eruptions because volcanic eruptions often emit gases.If that’s the case, volcanism could very well be the root cause of Venus’ thick cloud cover.And also, we have observed bursts of radio energy from the planet’s surface.These bursts are similar to what we see when volcanoes erupt on Earth.So this too suggests ongoing volcanic activity.But, although this is intriguing evidence, no one’s actually observed a Venus volcano erupting yet, so we can’t be positive.

  • 旁白:请听下面一段天文学课堂上的讲解。

    教授:几个世纪来许多人都对厚云层覆盖的金星有着深厚的兴趣,它被称之为神秘的星球。那么,云层下面是什么呢?金星的表面是什么样子呢?关于金星地表的一些问题还没有被解决,但是在过去的几年中我们也对之有所了解。首先,让我谈谈我们是如何穿过这些厚厚的云层。首先,是苏联的“金星二号”探测器,他直接着陆在金星表面并发回了它周围的图像。其次,我们在金星上空的卫星做了雷达成像。雷达可以穿过云层。所以我们都知道了什么呢?好,凯伦?

    学生:嗯,我记得读到过,并没有多大的收获,金星地表的大部分都十分平坦。

    教授:是的,大部分地区十分平坦,但是,并不全是这样。在其他地区,有火山、轮廓清晰的山谷、陨石坑、熔岩穹丘,这些熔岩的形状就像是巨大的薄饼。火山也是如此,金星地表最有意思的特征是火山的地盾。

    地盾是由于岩浆反复从一个地方喷出地表而形成的。记住,岩浆是地下热的熔化了的岩石,当流出地表后就称为岩浆,这样,岩浆构成并冷却成火山。金星的岩浆比较稀薄,它很容易就会喷出,所以火山的地盾比较平缓。他们被叫做盾状火山,是因为从上空看起来他们的形状比较像盾,就是战士的盾牌。

    十分有趣的是地球上的火山大部分都不是盾状火山。相反的,是其他种类的火山,例如,地层火山,是地球板块运动造成的。还记得地层火山吧?在地壳下方,有许多缓缓移动的板块。而在不同板块连接或互相作用的地区,存在着地球上大部分的火山。而在金星上,火山并不像在地球上一样在个别地区集中。相反地,它们很随机的分布在金星的表面。很是壮观,金星上大部分是盾状火山,它们的分布十分分散,这说明金星没有移动的地质板块这与地球十分的不同。在地球上,活动的地质板块是主要的地质因素,对整个地表的动态变化十分的重要,对不对?为什么金星没有地质板块呢?对此有几个理论,其中一个是说由于金星没有地表水,地表水可以为地质板块的运动起到润滑作用。就像在地球上一样。哦,我忘了提到,金星上没有地表水。

    学生:请等一下。您说地球上有盾状火山?您能举一个例子吗?

    教授:当然可以了。在太平洋的夏威夷岛上的火山就是盾状火山,它们是由地下喷出的岩浆构成的。所以在地球上的火山有很多种,而金星上的火山却差不多只有一种。艾瑞克?

    学生:金星上的火山是活火山吗?

    教授:嗯,这个问题很有意思。对于这个问题还存在着争论。这样讲吧。首先,金星云层中的二氧化硫的含量显示出大幅度并且频繁的波动。这些波动有可能是由二氧化硫一次又一次不断地骤增和骤减引起的,这可能这是由火山爆发引起的,因为火山爆发常常会发射出气体。如果是这样的话,火山活动很有可能是造成金星厚云盖的根本原因。而且我们观察到金星表面会爆发出电磁能量。这种爆发与我们在地球上看到的火山爆发相似。这也同样使人联想到火山活动。但尽管这个证据十分有吸引力,但是到目前为止并没有人真正的见过金星的火山爆发,所以我们无法肯定。

  • 官方解析
  • 网友贡献解析
  • 本题对应音频:
    0 感谢 不懂
    音频1
    解析

    题型分析:主旨题

    原文定位

    Professor: Many people have been fascinated about Venus for centuries because of its thick cloud cover, this so-called planet of mystery and all of that. Well, what's under those clouds? What's the surface of the planet like? Some questions about the surface are still unresolved but, but we have learned a lot about it in the past several years.

    选项分析

    章前面一开始教授说到Venus surface以前的一些研究,然后通过转折表达最近的研究其实不是smooth,列举了canyons, ripped valleys, meteor craters, lava domes,最后着重讲解了shield volcano 以及与Earth 的对比

    A选项即为文章核心关键词Venus surface的原文定位, 是对全文主旨最准确的概括

    标签

题目讨论

如果对题目有疑问,欢迎来提出你的问题,热心的小伙伴会帮你解答。

如何吃透这篇文章?

Shield Volcanoes on Venus

0人精听过

预计练习时间:16min16s

马上精听本文

最新提问