Milankovitch Hypothesis托福听力原文翻译及问题答案

Milankovitch Hypothesis托福听力原文翻译及问题答案

一、Milankovitch Hypothesis托福听力原文：

Narrator:Listen to part of a lecture in an environmental science class.

Male Professor:OK,so we've been talking about theories that deal with the effects of human activity on the climate,but today I’d like to talk a little bit about other theories that can explain variations in climate.And one of the,um,best known is called the Milankovitch hypothesis.Um,now what the Milankovitch hypothesis is about,um,it,it says that variations in Earth’s movements,specifically,in its orbit around the Sun...these variations lead to differences in the amount of solar energy that reaches Earth,and it’s these differences in the amount of energy that’s reaching Earth from the Sun,it’s what causes variations in Earth’s climate.

Okay,a lot of people think of Earth’s orbit around the Sun as being perfectly circular…as smooth and as regular as um,say the way hands move on a well-made watch.But..it just doesn’t work that way.You’re probably aware that the Earth’s orbit around the Sun,it’s not shaped like a perfect circle,it’s more of an oval,it’s elliptical.But the shape of this orbit isn't consistent,it varies over time,over a period of about 100,000 years.

Sometimes it's a little more circular,sometimes it’s more elliptical.And when Earth's orbit is more elliptical,Earth is actually closer to the Sun during part of the year,which makes Earth and in particular the Northern Hemisphere warmer.And why’s that important?Well,because most of the planet's glaciers are in the Northern Hemisphere,and if it gets too warm,then glaciers will stop forming and we already talked about how that affects Earth's overall temperature.The second movement involved in the hypothesis has to do with axial tilt,the tilt of Earth's axis,that imaginary pole that runs through the center of the Earth.And depending on the angle it tilts at,the seasons can be more or less severe–it makes winters cooler and summers warmer,or–what some might say it's doing now,it makes the summers less hot and,more importantly,the winters less cold,which,ah,just like what I mentioned before,can also stop,um,prevent glaciers from forming,or cause them to melt.There’s a third movement the hypothesis covers called precession.Precession,basically,is the change in the direction of the Earth's axis of rotation.It would take me a million years to explain even just the basics of this movement as precession is quite complex.And all of these details are way beyond our scope.What's important for you to understand is that these three movements,well,they're cyclical,and they work together to form,to produce complex but regular variations in Earth's climate,and lead to the growth or decline of glaciers.Now,when Milankovitch first proposed this theory in the 1920s,many of his colleagues were skeptical.Milankovitch didn't have any proof:Actually there wouldn't be any evidence to support his hypothesis until the 1970s,when oceanographers were able to drill deep into the seafloor and collect samples,samples which were then analyzed by geologists—

and from these samples,they were able to put together a history of ocean temperatures going back hundreds of thousands of years,and this showed that the Earth's climate had changed pretty much the way Milankovitch's hypothesis suggested it would.So this evidence was pretty strong support for the Milankovitch hypothesis,and by the 1980s,most people accepted this theory.

Um,however,in the late 1980s,some scientists were exploring Devils Hole,which is,ah,basically an extensive,water-filled cave,far from the ocean in Nevada in the western United States.Over millions of years,groundwater left deposits of a mineral called“calcite”on the rock within Devils Hole.And by studying these calcite deposits,we could determine the climate conditions...the temperatures over the last half-million years.

Well,the Devils Hole findings contradicted the ones obtained during the 1970s.So,basically,the question was,were the ages of one or both of the samples wrong?Or were scientists misunderstanding the significance of the evidence?Well,um,in the 1990s,a new study was done on the two samples,and the ocean floor samples were found to be correct,as were the samples from Devils Hole.And now it's generally believed that the samples from Devils Hole correspond to variations in local climate in the western United States,rather than global climate changes.

二、Milankovitch Hypothesis托福听力中文翻译：

旁白：在环境科学课上听一节课的一部分。

男教授：好的，我们一直在讨论关于人类活动对气候影响的理论，但今天我想谈谈其他可以解释气候变化的理论。其中最著名的是米兰科维奇假说。现在米兰科维奇假说是关于，它说，地球运动的变化，特别是在它围绕太阳的轨道上。。。这些变化导致到达地球的太阳能量的不同，正是这些从太阳到达地球的能量量的差异，才导致了地球气候的变化。

好的，很多人认为地球围绕太阳的轨道是完美的圆形……就像制作精良的手表上的手一样平滑和规则。但是它就是不能那样工作。你可能知道地球围绕太阳的轨道，它的形状不是一个完美的圆，它更像是一个椭圆形，它是椭圆的。但是这个轨道的形状并不一致，它随时间而变化，在大约100000年的时间里。

有时它更圆，有时更椭圆。当地球的轨道更椭圆时，地球实际上在一年中的部分时间离太阳更近，这使得地球，尤其是北半球更温暖。为什么这很重要？嗯，因为地球上的大多数冰川都在北半球，如果温度过高，冰川就会停止形成，我们已经讨论过这会如何影响地球的整体温度。假设中涉及的第二个运动与轴向倾斜有关，即地轴的倾斜，即穿过地心的假想磁极。根据倾斜角度的不同，季节可能会更严重或更不严重-它使冬天更凉爽，夏天更温暖，或者-有些人可能会说它现在正在做的事情，它使夏天不那么热，更重要的是，冬天不那么冷，这，啊，就像我之前提到的，也可以阻止，嗯，防止冰川形成，或导致冰川融化。这个假设涵盖了第三个运动，叫做进动。进动基本上是地球自转轴方向的变化。我花了一百万年来解释这个运动的基本原理，因为进动相当复杂。所有这些细节都远远超出了我们的范围。对你们来说，重要的是要了解这三种运动，嗯，它们是周期性的，它们共同作用形成，在地球气候中产生复杂但有规律的变化，并导致冰川的增长或下降。现在，当米兰科维奇在20世纪20年代首次提出这个理论时，他的许多同事都持怀疑态度。米兰科维奇没有任何证据：实际上，直到20世纪70年代，海洋学家才能够深入海底并采集样本，然后由地质学家分析样本，才有任何证据支持他的假设-

从这些样本中，他们能够总结出几十万年前海洋温度的历史，这表明地球的气候已经发生了很大的变化，就像米兰科维奇的假设所表明的那样。因此，这一证据有力地支持了米兰科维奇假说，到了20世纪80年代，大多数人接受了这一理论。

嗯，然而，在20世纪80年代末，一些科学家在探索魔鬼洞，这是，啊，基本上是一个广泛的，充满水的洞穴，远离美国西部内华达州的海洋。数百万年来，地下水在魔鬼洞的岩石上留下了一种叫做“方解石”的矿物沉积物。通过研究这些方解石矿床，我们可以确定气候条件。。。过去50万年的气温。

嗯，魔鬼洞的发现与20世纪70年代的发现相矛盾。所以，基本上，问题是，一个或两个样本的年龄是否错误？还是科学家误解了证据的重要性？嗯，在20世纪90年代，对这两个样本进行了一项新的研究，发现海底样本是正确的，就像魔鬼洞的样本一样。现在人们普遍认为，来自魔鬼洞的样本对应的是美国西部当地气候的变化，而不是全球气候变化。

三、Milankovitch Hypothesis托福听力问题：

Q1:1.What is the lecture mainly about?

A.A hypothesis that explains how changes in Earth’s motions affect climate

B.A hypothesis that explains why the shape of Earth’s orbit varies over time

C.Reasons it is difficult to find evidence to support hypotheses about the climate

D.Analyses of the accuracy of data collected in different ways

Q2:2.Why does the professor compare Earth’s movements to a watch?

A.To clarify a common misunderstanding

B.To show in what way Earth is similar to a watch

C.To emphasize the regularity of Earth s movements

D.To connect the concepts of orbits and time

Q3:3.Why does the professor mention Northern Hemisphere glaciers?

A.They have a significant effect on the axial tilt of Earth.

B.They play a moderating role on Earth's climate.

C.Their formation could be affected by changes in Earth s orbit.

D.Their melting could result in longer warm seasons.

Q4:4.What is the significance of the evidence found on the ocean floor?

A.It negated earlier evidence that Milankovitch found.

B.It led to the development of new methods to measure global climate changes.

C.It helped Milankovitch first formulate his hypothesis.

D.It confirmed Milankovitch’s hypothesis.

Q5:5.What did calcite deposits from Devils Hole reveal?

A.Inaccurate information about long-term climate changes

B.Evidence that contradicted Milankovitch s hypothesis

C.Evidence that climate changes occur only locally

D.Variations in Earth's orbit that had little impact on climate

Q6:6.Why does the professor say this:

A.To inform the students about what he will not discuss.

B.To indicate the difficulty of measuring precession.

C.To explain why he plans to spend a long time discussing precession.

D.To clarify that he will provide additional information later.

四、Milankovitch Hypothesis托福听力答案：

A1:正确答案：A

A2:正确答案：A

A3:正确答案：C

A4:正确答案：D

A5:正确答案：B

A6:正确答案：A

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