1、1 Theres a dimmer switch inside the t causes its brightness to rise nd fall on timescales of around 100,000 years - exactly the same period as n ice ages on Earth. So says a physicist who has created a computer m of our stars core.2 Robert Ehrlich of e Mason University in Fairfax, Virginia, led effe

2、ct of temperature fluctuations in the sunserior. According to the stan dard view, the temperature of the suns core is held constant by the res of gravity and nuclear fu variations should be. However, Ehrlich t 3 He took as his starting the work of Attila Grandpierre of the Observatory of garian Acad

3、emy of . In 2005, Grandpierre a collaborator, Gbor goston, t magnetic he core could produce small instabilities in the solar plasma. These instabilities w ould induce localised oscillations in temperature.4 Ehrlichs t whilst most of these oscillations cancel each her out, some reinforce one another

4、e long-lived temperature tions. The favoured frequencies allow the suns core temperature to around its average temperature of 13.6 million kelvins in cycles lasting either 100,000 or 41,000 years. Ehrlich sayst randomeractions within the sun s magnetic field could flip the fluctuations from one cycl

5、e length to the 5 These two timescales are instantly recognisable to anyone familiar with Eart hs ice ages: for the past million years, ice ages have occurred roughly every 100,000 years. Before t, they occurred roughly every 41,000 years.6 Most scientists t the ice ages are the result of subtle cha

6、nges Earths orbit, known as the ovitch cycles. One such cycle describes way Earths orbit gradually changes from a circle to a lipse nd back again roughly every 100,000 years. The theory says this alters the mount of solar radiation t Earth receives, triggering the ice ages. However, a persistent pro

7、blem with this theory has been its inability to explain why th e ice ages changed frequency a million years ago.7 In ovitch, there is certainly no good idea why the frequency change from one to another, says Neil Edwards, a climatologist at the University in Milton Keynes, UK. Nor is the transition

8、problem the only one th e Mil ovitch theory fa . Ehrlich and other critics claim t the temperatu re variations caused by Mil ovitch cycles are simply not big enough to drive ice ages.8 However, Edwards ves the small changes in solar heating produced ovitch cycles are lified by feedback mechanisms on

9、 Earth. le, if sea ice begins to form because ofovitch cycles are lified by feedback mechanisms on Earth. le, if sea ice begins to form because of a slight cooling, carbon t would otherwise have found its o the atmosphere as part of carbon cycle is lockedo the ice.t weakens the greenhouse effect and

10、 E arth grows even colder.9 According to Edwards, there is no lack of echanisms. If you add eir effects together, there is n enough feedback to make work, he says. The problem now is identifying echanisms are at ork. This is why scientists like Edwards are not yet ready to give up on current theory.

11、 Mil ovitch 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 cant see any way of testing Ehrlichs idea to s ee where we are in the temperature oscillation.10 Ehrlich concedes this. If there is a way

12、 to test this theory on the sun, I cant think of onet is practical, he says.ts 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 smallert of the sun, and so Ehrlich bet the oscillatio

13、n periods could be short enough to be observed. He has yet to calculate the precise period or th e extent of variation in brightness to be expected.11 Nigel Weiss, a solar physicist at the University of Cambridge, is far from c onvinced. He describes Ehrlichs claims as utterly implausible. Ehrlich t

14、 Weisss opinion is based on the standard solar , which fails to o account the magnetic instabilitiest cause the temperature fluctuati Do the following sements agree with the information given in the r eading passage?TRUE if the sement is true according to the passage FALSE if the sement is false acc

15、ording to the passage NOT GIVEN if the information is not given in the passage1. The ice ages changed frequency from 100,000 to 41,000 years a million y ears ago.2. The sole t the ovitch theory can not solve is to why the ice age frequency should shift from one 3. Carbon dioxide can be locked artifi

16、 house effect.o ice to eliminate the 4. Some scientists are not ready to give up the ovitch theory though ey havent figured out whi lify the changes in solar 5. Both Edwards and Ehrlich t there is no practical way to test en the solar temperature oscillation begins and when 1. 】en the solar temperat

17、ure oscillation begins and when 1. 】 躍起來，變得興奮”。比如：The spokesman implicitly condemned the United policy switch. 發(fā)言人含蓄地譴責政策上的轉變。再比如：Every time I switch n the TV, theres football. Its 次打開電視都是足，真是受不了2. fluctuation這個詞在本篇文章中表示“波動”，例如：The calculations do not oaccount any fluctuation in the share price. 這些計

18、算沒有考慮到股價的波動。又例如： A firm secures a needed commodity and is protected against price fluctuation.3. collaborator 這個詞表示“協(xié)作者”，詞根 collaborate“合作”。近義詞 cooperator“合作者”例如：I need a collaborator to help me. 我需要個人跟我合作,忙。又如：His ollaborator, Hooke, was of a different opinion. 他的合作持有不同的看法4. oscillation在文中的意思是“振蕩”，

19、例如：Some oscillation of the fuselage had been noticed on early flights. 在之前的幾次飛行中，就已經(jīng)察覺到機身有些搖晃。再例如：Itsoscillation depends on the strength of the ional field. 它的振動幅度取5. orbit指的是“軌道”o orbit“最佳狀態(tài)”。例如：The planet is probably orbit around a small star. 這顆行星可能正環(huán)繞著一顆小恒星運行。又如：Yet bigger alites will be sent o

20、orbit. 更為大【與】See para.5: for the past million years, ice ages have occurred roughly every 100,000 years. Beforet, they occurred roughly every 41,000 years.2. See para.7: In ovitch, there is certainly no good idea why the cy should change from one to another, . Nor is the transition problem the only

21、one the Milovitch theory fa3. Not See para.8: if sea ice begins to form because of a slight cooling, carbon de is o the t weakens the greenhouse effect. (The e doesnt mention anything about locking o ice 9 According to Edwards, there is no lack of echanisms. If you add eir effects together, there is n enough feedback to make work, he says. The problem now is identifying echanisms are at ork. This is why ork. This is why scientists like Edwards are not yet ready to give up on the current theory. Milovitch cycles give us ice ages roughly when we observe them to happen. We can calculate whe