NASA Focuses on Earth-Like Planets
For decades, looking for life elsewhere in the universe meant listening for signals that could be from distant civilizations. But recent breakthroughs in space technology refocused some of that effort toward finding planets that may harbor life, even in its primitive form.
When NASA launched the Kepler Space Telescope in 2009, scientists learned something new - and quite significant, says the director of the Space Telescope Science Institute, Matt Mountain.
“Our galaxy has at least 100 billion planets in it. And we didn't know that five years ago," said Mountain.
Of course, Kepler and today's other powerful telescopes cannot actually see those planets; they are too faint against the light of their stars.
But scientists can measure the change of light when they pass in front of the star and analyze the light passing through their atmosphere to determine what is in it.
“Well, if we were looking at Earth, we would see signs of our sky, our blue sky, we would see signs of oxygen, of carbon-dioxide, of sulfur dioxide from volcanoes and we might even see signatures that there was plant life," said NASA's astrophysicist and former astronaut John Grunsfeld. "And we see that by dissecting the light into its component colors."
Most of the planets discovered so far are unlike Earth. They are too big, too small, too close to their sun, or too far away to support life. But astrophysicist Sara Seager says small planets the size of Earth are extremely common.
“We're looking for biological signatures, gasses that are produced by life, gasses that don't belong in the atmosphere," said Seager.
In cooperation with the European Space Agency and scientists from other nations, NASA is building the next generation of space telescopes that may be able to find evidence of life.
The James Webb Space Telescope, scheduled to be deployed in 2018, will have unprecedented sensitivity and resolution that will greatly improve the spectroscopic analysis of distant stars and planets.
NASA’s chief scientist Ellen Stofan says the agency also plans to look for life on Jupiter’s moon Europa, which may have an ocean under its ice cover.
“In our own solar system we know where to go, we know what to measure it and we're in the process of doing just that. Looking out, beyond our solar system, we're on the right track, we're making the right measurements and we're just on the cusp of learning so much," said Stofan.
Scientists say there's a very high probability that they will find a planet very much like Earth. That could help answer the question: how hard is it for life to get a foothold in the universe?
詞匯解析
budget
難度：4星核心詞匯，屬常用3000詞
英漢解釋
n.預算
vt.編預算；為 ... 做預算
vi.節(jié)省開支
adj.廉價的；不貴的
參考例句
用作名詞 (n.)
Congress has approved the new educational budget.
國會通過了新的教育預算。
用作及物動詞 (vt.)
The government has budgeted 10000000 pounds for education spending.
政府將10000000英鎊編入教育預算。
用作不及物動詞 (vi.)
If we budget carefully, we'll be able to afford a new house.
如果我們精打細算就能買一座新房子了。
用作形容詞 (adj.)
You can buy high-quality goods at budget prices there.
你可以在那買到物美價廉的商品。
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contain
難度：5星基本詞匯，屬常用1000詞
英漢解釋
vt.容納；包含；抑制；克制
vi.自制
參考例句
用作及物動詞 (vt.)
The atlas contains forty maps.
這個地圖集有四十幅地圖。
用作不及物動詞 (vi.)
She couldn't contain herself for joy.
她高興地難以自制。
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expert
難度：4星核心詞匯，屬常用3000詞
英漢解釋
n.專家；能手
adj.熟練的；內(nèi)行的
參考例句
用作名詞 (n.)
She is a reputable expert.
她是個有聲望的專家。
用作形容詞 (adj.)
The surgeon cut away the tumour with expert skill.
外科大夫用熟練的技術(shù)把腫瘤切去。
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virus
難度：4星核心詞匯，屬常用3000詞
英漢解釋
n.病毒；病原體
參考例句
用作名詞 (n.)
Scientists have isolated the virus causing the epidemic.
科學家們已分離出引起這種流行病的病毒。
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funeral
難度：3星常用詞匯，屬常用6000詞
英漢解釋
adj.葬禮(的)
n.葬禮
參考例句
用作形容詞 (adj.)
Their cars headed the funeral procession.
他們的車隊在葬禮隊伍的最前面。
用作名詞 (n.)
They held a state funeral in honour of the statesman.
他們?yōu)檫@位政治家舉行了國葬。
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deportation
英漢解釋
n.驅(qū)逐；驅(qū)逐出境；放逐
參考例句
用作名詞 (n.)
Years ago convicted criminals in England could face deportation to Australia.
很多年以前，英國已定罪的犯人可能被驅(qū)逐到澳大利亞。
Deportation of criminals from England to Australia was once common.
把犯人從英國放逐到澳大利亞的作法在過去曾一度盛行。
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agent
難度：5星基本詞匯，屬常用1000詞
英漢解釋
n.代理人；代理商；藥劑；特工人員
參考例句
用作名詞 (n.)
I have been instructed by my agent that you still owe me 100 pounds.
我的代理人通知我，你還欠我100磅。
The officer inspired the secret agent to murder the president .
這個軍官鼓動這個特工人員去謀殺總統(tǒng)。
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respond
難度：4星核心詞匯，屬常用3000詞
英漢解釋
v.回答；響應(yīng)；反應(yīng)；反應(yīng)靈敏；反響
n.[建]壁聯(lián)；[宗]應(yīng)唱圣歌
參考例句
用作動詞 (v.)
I invited her to dinner but she did not respond.
我請她吃晚飯，但她未作回答。
The professor lectured with a beaming countenance, but the students didn't respond much, only agreeing with what he said.
教授講得眉飛色舞，學生們卻沒有太大的反響，只是隨聲應(yīng)和。
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