雅思阅读模拟题及答案详解 Sun‘s fickle heart may leave us cold

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带来雅思阅读精选之"Sun‘s fickle heart may leave us cold"，文章摘自新科学家(New

Scientist)。所有雅思阅读方法技巧都需要反复做题去巩固，自己不足的地方也只有通过做题才能显现。练习也是有技巧的，不能盲目瞎做。把每一次阅读练习都当做考试，时间一个小时，三篇阅读，没有手机，没有字典，没有参考资料，没有笔记。只有这样，在考场上才有可能在50分钟内做完题目(十分钟的誊写答案以及检查时间)。强势推广：雅思阅读精品资料，右手边戳链接→_→防脱发秘笈之——雅思阅读精读资料(广而告之，攒人品，爆高分)

良心安利：雅思考试阅读精选及超详解【汇总】

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1.雅思阅读材料

Sun's fickle heart may leave us cold

From New Scientist. Stuart Clark

1 There's a dimmer switch inside the sun that causes its brightness to rise

and fall on timescales of around 100，000 years - exactly the same period as

between ice ages on Earth. So says a physicist who has created a computer model

of our star's core.

2 Robert Ehrlich of George Mason University in Fairfax， Virginia， modelled

the effect of temperature fluctuations in the sun's interior. According to the

standard view， the temperature of the sun's core is held constant by the

opposing pressures of gravity and nuclear fusion. However， Ehrlich believed that

slight variations should be possible.

3 He took as his starting point the work of Attila Grandpierre of the Konkoly

Observatory of the Hungarian Academy of Sciences. In 2005， Grandpierre and a

collaborator， Gábor ágoston， calculated that magnetic fields in the sun's core

could produce small instabilities in the solar plasma. These instabilities would

induce localised oscillations in temperature.

4 Ehrlich's model shows that whilst most of these oscillations cancel each

other out， some reinforce one another and become long-lived temperature

variations. The favoured frequencies allow the sun's core temperature to

oscillate around its average temperature of 13.6 million kelvin in cycles

lasting either 100，000 or 41，000 years. Ehrlich says that random interactions

within the sun's magnetic field could flip the fluctuations from one cycle

length to the other.

5 These two timescales are instantly recognisable to anyone familiar with

Earth's ice ages： for the past million years， ice ages have occurred roughly

every 100，000 years. Before that， they occurred roughly every 41，000 years.

6 Most scientists believe that the ice ages are the result of subtle changes

in Earth's orbit， known as the Milankovitch cycles. One such cycle describes the

way Earth's orbit gradually changes shape from a circle to a slight ellipse and

back again roughly every 100，000 years. The theory says this alters the amount

of solar radiation that Earth receives， triggering the ice ages. However， a

persistent problem with this theory has been its inability to explain why the

ice ages changed frequency a million years ago.

7 "In Milankovitch， there is certainly no good idea why the frequency should

change from one to another，" says Neil Edwards， a climatologist at the Open

University in Milton Keynes， UK. Nor is the transition problem the only one the

Milankovitch theory faces. Ehrlich and other critics claim that the temperature

variations caused by Milankovitch cycles are simply not big enough to drive ice

ages.

8 However， Edwards believes the small changes in solar heating produced by

Milankovitch cycles are then amplified by feedback mechanisms on Earth. For

example， if sea ice begins to form because of a slight cooling， carbon dioxide

that would otherwise have found its way into the atmosphere as part of the

carbon cycle is locked into the ice. That weakens the greenhouse effect and

Earth grows even colder.

9 According to Edwards， there is no lack of such mechanisms. "If you add

their effects together， there is more than enough feedback to make Milankovitch

work，" he says. "The problem now is identifying which mechanisms are at work."

This is why scientists like Edwards are not yet ready to give up on the current

theory. "Milankovitch cycles give us ice ages roughly when we observe them to

happen. We can calculate where we are in the cycle and compare it with

observation，" he says. "I can't see any way of testing [Ehrlich's] idea to see

where we are in the temperature oscillation."

10 Ehrlich concedes this. "If there is a way to test this theory on the sun，

I can't think of one that is practical，" he says. That's because variation over

41，000 to 100，000 years is too gradual to be observed. However， there may be a

way to test it in other stars： red dwarfs. Their cores are much smaller than

that of the sun， and so Ehrlich believes that the oscillation periods could be

short enough to be observed. He has yet to calculate the precise period or the

extent of variation in brightness to be expected.

11 Nigel Weiss， a solar physicist at the University of Cambridge， is far from

convinced. He describes Ehrlich's claims as "utterly implausible". Ehrlich

counters that Weiss's opinion is based on the standard solar model， which fails

to take into account the magnetic instabilities that cause the temperature

fluctuations.(716 words)

2.雅思阅读题目

Questions 1-4

Complete each of the following statements with One or Two names of the

scientists from the box below.

Write the appropriate letters A-E in boxes 1-4 on your answer sheet.

A. Attila Grandpierre B. Gábor ágoston C. Neil Edwards D. Nigel Weiss E.

Robert Ehrlich

1. ……claims there抯 a dimmer switch inside the sun that causes its brightness

to rise and fall in periods as long as those between ice ages on Earth.

2. ……calculated that the internal solar magnetic fields could produce

instabilities in the solar plasma.

3. ……holds that Milankovitch cycles can induce changes in solar heating on

Earth and the changes are amplified on Earth.

4. ……doesn't believe in Ehrlich's viewpoints at all.

Questions 5-9

Do the following statements agree with the information given in the reading

passage?

In boxes 5-9 on your answer sheet write TRUE if the statement is true

according to the passage FALSE if the statement is false according to the

passage NOT GIVEN if the information is not given in the passage

5. The ice ages changed frequency from 100，000 to 41，000 years a million

years ago.

6. The sole problem that the Milankovitch theory can not solve is to explain

why the ice age frequency should shift from one to another.

7. Carbon dioxide can be locked artificially into sea ice to eliminate the

greenhouse effect.

8. Some scientists are not ready to give up the Milankovitch theory though

they haven't figured out which mechanisms amplify the changes in solar

heating.

9. Both Edwards and Ehrlich believe that there is no practical way to test

when the solar temperature oscillation begins and when ends.

Questions 10-14

Complete the notes below.

Choose one suitable word from the Reading Passage above for each answer.

Write your answers in boxes 10-14 on your answer sheet.

The standard view assumes that the opposing pressures of gravity and nuclear

fusions hold the temperature ……10……in the sun's interior， but the slight changes

in the earth's ……11…… alter the temperature on the earth and cause ice ages

every 100，000 years. A British scientist， however， challenges this view by

claiming that the internal solar magnetic ……12…… can induce the temperature

oscillations in the sun's interior. The sun's core temperature oscillates around

its average temperature in ……13…… lasting either 100，000 or 41，000 years. And

the ……14…… interactions within the sun's magnetic field could flip the

fluctuations from one cycle length to the other， which explains why the ice ages

changed frequency a million years ago.

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