2016年职称英语考试《综合A》阅读理解真题及答案

Black Holes Trigger Stars to Self-Destruct

Scientists have long understood that supermassive black holes weighingmillions or billions of suns can tear apart stars that come too close. The blackhotels gravity pulls harder on the nearest part of the star, an imbalance thatpulls the star apart over a period of minutes or hours, once it gets closeenough.

Scientists say this Uneven pulling is not the only hazard facing the star.The strain of these unbalanced forces can also trigger a nuclear explosionpowerful enough to destroy the star from within. Matthieu Brassart andJean-Pierre Luminet of the Observatoire de Paris in Meudon, France, carried outcomputer simulations of the final moments of such an unfortunate star's life,asit veered towards a supermassive black hole.

When the star gets close enough, the uneven forces flatten it into a pancakeshape. Some previous studies had suggested this flattening would increase thedensity and temperature inside the star enough to trigger intense nuclearreactions that would tear it apart. But other studies had suggested that thepicture would be complicated by shock waves generated during the flatteningprocess and that no nuclear explosion should occur.

The new simulations investigated the effects of shock waves in detail,andfound that even when their effects are included,the conditions favor a nuclearexplosion. "There will be an explosion of the star-it will be completelydestroyed," Brassart says. Although the explosion obliterates the star, it savessome of the star's matter from being devoured by the black hole. The explosionis powerful enough to hurl much of the star's matter out of the black hole'sreach, he says.

The devouring of stars by black holes may already have been observed,although at a much later stage. It is thought that several months after theevent that rips the star apart,its matter starts swirling into the hole itself.It heats up as it does so, releasing ultraviolet light and X-rays.

If stars disrupted near black holes really do explode, then they could inprinciple allow these events to be detected at a much earlier stage, says JulesHatpern of Columbia University in New York, US. "It may make it possible to seethe disruption of that star immediately if it gets hot enough," he says.

Brassart agrees. "Perhaps it can be observed in the X-rays and gamma rays,but it's something that needs to be more studied," he says. Supernova researcherChris Fryer of the Los Alamos National Laboratory in Los Alamos, New Mexico, US,says the deaths of these stars are difficult to simulate, and he is not surewhether the researchers have proven their case that they explode in theprocess.

36.题干】Something destructive could happen to a star that gets too close to ablack hole. Which of the following destructive statements is NOT mentioned inthe passage?

选项】

A.The black hole could tear apart the star.

B.The black hole could trigger a nuclear explosion in the star.

C.The black hole could dwindle its size considerably.

D.The black hole could devour the star.

答案】C

解析】

37.题干】According to the third paragraph, researchers differed from each otherin the problem of_____

选项】

A.whether nuclear reaction would occur.

B.whether the stars would increase its density and temperature.

C.whether shock waves would occur.

D.whether the uneven forces would flatten the stars.

答案】A

解析】

38.题干】According to the fourth paragraph, which of the following is NOTtrue?

选项】

A.No nuclear explosion would be triggered inside the star.

B.The star would be destroyed completely.

C.Much of the star's matter thrown by the explosion would be beyond the blackhole's reach.

D.The black hole would completely devour the star.

答案】D

解析】

39.题干】What will happen several months after the explosion of the star?

选项】

A.The star's matter will move further away from by the black hole.

B.The black hole’s matter will heat up.

C.The torn star's matter will swirl into the black hole.

D.The black hole's matter will release ultraviolet light and X-rays.

答案】C

解析】

40.题干】According to the context, the word "disruption" in Paragraph 6means_____

选项】

A."Confusion."

B."Tearing apart."

C."Interruption."

D."Flattening."

答案】B

解析】

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