移居外星不是梦？

由于Trappist-1又小又冷，让围绕它的7颗行星非常温暖，意味着这些行星上可能存在液态水，甚至是生命。研究人员认为，这可能是太阳系以外，最适合人类居住的地方，并指出在太阳系以外发现宜居行星是十分罕见的。

测试中可能遇到的词汇和知识：

light year[天] 光年

Belgium比利时（首都是布鲁塞尔）['bɛldʒəm] orbit轨道；眼眶；势力范围['ɔːbɪt]

dimly朦胧地；微暗['dɪmli]

tidal潮汐的；潮的['taɪd(ə)l]

阅读马上开始，建议您计算一下阅读整篇文章所用的时间，对照下方的参考值就可以评估出您的英文阅读水平。

Astronomers make largest ever discovery of habitable planets（254 words）

By Clive Cookson,Science Editor

Astronomers have identified the largest group of potentially habitable planets yet discovered,about 40 light years away from Earth.

An international team led by Liège university in Belgium made the discovery of the planetary system,three of whose seven Earth-sized worlds have conditions in which life could have evolved. Their findings,reached by combining observations from a dozen telescopes on mountaintops and in space,are published in the journal Nature.

The planets orbit a relatively cool red dwarf star called Trappist-1 that has just 8 per cent of the sun’s mass and 0.5 per cent of its light output.

Until now the hunt for planets in the galaxy beyond our solar system,known as exoplanets,has concentrated on sun-like stars,around which more than 3,500 have been detected. The Trappist-1 discovery marks the start of a new search focusing on red dwarfs,which are more plentiful than larger stars.

“The energy output from dwarf stars like Trappist-1 is much weaker than that of our sun,”said Amaury Triaud,a team member at Cambridge university.“Planets would need to be in far closer orbits than we see in the solar system if there is to be surface water. Fortunately,it seems that this kind of compact configuration is just what we see around Trappist-1.”

Because the Trappist-1 system is relatively close to Earth in galactic terms and because its parent star is a dimly shining dwarf,astronomers predict that it will be easier to study than most exoplanets associated with dazzlingly bright sun-like stars.

请根据你所读到的文章内容，完成以下自测题目：

1.How many planets of this planetary system have conditions in which life could have evolved according to the study?

A.3

B.7

C.8

D.40

答案 ⁽¹⁾

2.How many telescopes on mountaintops and in space to observe?

A.7

B.12

C.40

D.120

答案 ⁽²⁾

3.Which one is not right about Trappist-1?

A.it is at a high temperature

B.it has 8% of the sun’s mass

C.it has 0.5% of sun’s light output

D.it is relatively close to Earth in galactic terms

答案 ⁽³⁾

4.Which one is not mentioned as the reason to make it easier to study than others?

A.the Trappist-1 system is relatively close to Earth

B.its parent star is a dimly shining dwarf

C.it is without too dazzlingly bright

D.it is rocky body about the same size as Earth

答案 ⁽⁴⁾

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(1) 答案：A.3解释：由比利时列日大学(University of Liège)牵头的一个国际小组发现了该行星系。该行星系中有7个与地球大小类似的行星，其中3个具有可能孕育生命的条件。

(2) 答案：B.12解释：原文“a dozen”，天文学家结合在山顶和太空的12个望远镜的观察结果得出了这一发现。

(3) 答案：A.it is at a high temperature解释：这些行星在围绕一个名为Trappist-1的温度相对较低的红矮星的轨道运行，该恒星的质量仅为太阳的8%，其能量输出仅为太阳的0.5%。

(4) 答案：D.it is rocky body about the same size as Earth解释：因为在整个银河系中Trappist-1星系距离地球相对较近、其母星又是光度较弱的矮星，天文学家预测，相比其他大多数与光度较强、和太阳类似的恒星相关的系外行星，该星系更易研究。 6a7eXRdcknLWmGlAf/gMdjLa2CDBTWzaY/iL5dAjj0wRK8N0aAfTnDsbT7FgSADZ