英语听力：自然百科 已知的宇宙：外星生命 Alien_Contact-5

 Because from trillions of miles away, these small planets get lost in the blinding glare of their stars’ brightness.

 

"The sad truth of the matter is that earth-like planets are near cosmic specks² of dust. And therefore detecting them is really quite hard."

 

Hard, but not impossible. Every now and again, the planet passes directly between us and the star. And if it does that, it's like a little eclipse. And the star-light drops. It gets darker because the planet is blocking the light from that star. And it turns out we can see that.

 

With this in mind, scientists built one of the world’s most sensitive telescopes and launched it into space. The mission called Kepler may not help us find E.T, but it could help us find its home.

 

"Kepler will simply do one thing unbelievably well--measure the brightness of 100,000 stars over and over and over, looking for a few of those 100,000 stars that dim."

 

Seeing the tiniest dim from a small planet travelling in front of a star thousands of light-years away isn’t easy to imagine. But the Kepler telescope is one of the most sensitive cameras ever built.

 

"To give you an idea of just how sensitive Kepler is, I’m gonna demonstrate using this massive World War II search light. The brightness of that search light represents the extreme luminosity of stars. And I’m gonna use this tiny marble to represent the planet. When this planet passes in front of the star, it blocks out a tiny fraction of the light, dimming the star by a very small amount, and that’s exactly what the Kepler space craft can detect."

 

Kepler can detect a 0.01% change in the star’s luminosity, but even if it spots a dimming star, there’s still another problem. 

 

"When Kepler sees a star that dims, it could be due to a speck¹ of dust that crossed in front of the telescope. There’s a possibility of binary³ stars, two stars that orbit each other thereby⁴ dimming the stars as one blocks the other."

 

1 speck   

n.微粒，小污点，小斑点

参考例句：

• I have not a speck of interest in it.我对它没有任何兴趣。
• The sky is clear and bright without a speck of cloud.天空晴朗，一星星云彩也没有。

2 specks   

n.眼镜；斑点，微粒，污点( speck的名词复数 )

参考例句：

• Minutes later Brown spotted two specks in the ocean. 几分钟后布朗发现海洋中有两个小点。 来自英汉非文学 - 百科语料821
• Do you ever seem to see specks in front of your eyes? 你眼睛前面曾似乎看见过小点吗？ 来自辞典例句

3 binary   

adj.二，双；二进制的；n.双(体)；联星

参考例句：

• Computers operate using binary numbers.计算机运行运用二进位制。
• Let us try converting the number itself to binary.我们试一试，把这个数本身变成二进制数。

4 thereby   

adv.因此，从而

参考例句：

• I have never been to that city,,ereby I don't know much about it.我从未去过那座城市，因此对它不怎么熟悉。
• He became a British citizen,thereby gaining the right to vote.他成了英国公民，因而得到了投票权。