VOA标准英语2010年-Five New Planets Discovered by NASA's

Artist's conception of the Kepler spacecraft, launched in 2008 to identify planets orbiting distant stars

 
Related Links
Kepler
"The planets we found are all hotter than molten lava¹. ... Looking at them might be like looking at a blast furnace.

Scientists on Monday reported the first new worlds discovered by the Kepler Space Telescope, which was launched in March last year specifically to find planets orbiting distant stars.

Kepler was designed to look for planets like Earth, but the first discoveries are much bigger planets - four of them bigger than Jupiter, and a fifth roughly the size of Neptune².

NASA scientist William Borucki says these planets race around their stars so fast, that their years are measured in days.

"The orbital periods run from about 3.2 days to 4.9 days. So these are very short orbits. The short period orbits also tell us that the planets are orbiting close to their stars, and consequently you're going to see they're quite hot."

How hot? Astronomers⁴ use the Kelvin scale, which starts at absolute zero. So, frigid⁵ Jupiter is 124 Kelvin, Earth is about 300 Kelvin. "If you continue going up in temperature, you see molten lava at about 1300 Kelvin," said Borucki. "The planets we found are all hotter than molten lava. They all simply glow with their temperatures. Looking at them might be like looking at a blast furnace. They are very bright in their own right."

Borucki and other Kepler astronomers discussed the newly-discovered planets at the American Astronomical⁶ Society meeting in Washington.

The Kepler orbiting telescope can't see planets directly. Looking into deep space with even the best telescope, you can't see a planet next to the large, bright glare of the star it's orbiting. So instead, astronomers look for the light of the star to dim slightly as a planet passes in front of it. That's how the five new worlds were identified.

Kepler is continuously monitoring more than 100,000 stars considered likely to have planets. The challenge is weeding out false positives, when a star dims for some other reason.

"Well, fortunately we have a very well laid out plan for vetting⁷ out these false positives," explained San Jose State University astronomer³ Natalie Batalha.

She told reporters that some of those false positives can be eliminated by the precision and stability of Kepler's observations. But in other cases, astronomers rely on ground-based observations to confirm findings from Kepler. It required almost 100 nights of observations from telescopes in the U.S. and the Canary Islands to confirm discovery of the five planets reported this week

"So that gives you a feel for the process, how long it takes from start to finish and how careful we are in confirming and making sure these are real signals," she said.

Kepler's high precision is not just useful in identifying new planets around distant stars. It can tell astronomers something about the stars themselves, as well as providing more detailed⁸ information about the planets it is discovering.

Ron Gilliland of the Space Telescope Science Institute says the size of one star was measured by ground telescopes to an accuracy of plus or minus 10 percent; with Kepler, the uncertainty⁹ was reduced to just 1 percent. And likewise, Kepler has refined measurements of a planet in orbit around that star.

"Before Kepler, we would have known the density¹⁰ of the exoplanet orbiting this star to maybe 50 percent accuracy. After Kepler, we should know that to about 5 percent accuracy. And that's absolutely critical to hope to understand the interior structure of the planets." 

One other conclusion from these first Kepler observations: many of the 100,000-plus stars in Kepler's sights are less active than had been expected - less active in the sense of having fewer storms that would give off bursts of radiation that might threaten life on planets orbiting them.

Caty Pilachowski of Indiana University says this bodes¹¹ well for those hoping to find conditions that are hospitable¹² to life on these distant planets.

"It's good news for astrobiology because if most stars are quiescent¹³, if stars don't become terribly active, then they don't scour¹⁴ the surfaces of their planets, and we're more likely to have habitats where life might evolve. And it increases our chances of finding that life down the road." 

Scientists working with Kepler say they're happy with the results they're getting. And they're looking forward to collecting a lot more data in the months and years to come that will enable them to identify planets more like Earth.

1 lava   

n.熔岩，火山岩

参考例句：

• The lava flowed down the sides of the volcano.熔岩沿火山坡面涌流而下。
• His anger spilled out like lava.他的愤怒像火山爆发似的迸发出来。

2 Neptune   

n.海王星

参考例句：

• Neptune is the furthest planet from the sun.海王星是离太阳最远的行星。
• Neptune turned out to be a dynamic,stormy world.海王星原来是个有生气、多风暴的世界。

3 astronomer   

n.天文学家

参考例句：

• A new star attracted the notice of the astronomer.新发现的一颗星引起了那位天文学家的注意。
• He is reputed to have been a good astronomer.他以一个优秀的天文学者闻名于世。

4 astronomers   

n.天文学者，天文学家( astronomer的名词复数 )

参考例句：

• Astronomers can accurately foretell the date,time,and length of future eclipses. 天文学家能精确地预告未来日食月食的日期、时刻和时长。 来自《简明英汉词典》
• Astronomers used to ask why only Saturn has rings. 天文学家们过去一直感到奇怪，为什么只有土星有光环。 来自《简明英汉词典》

5 frigid   

adj.寒冷的，凛冽的；冷淡的；拘禁的

参考例句：

• The water was too frigid to allow him to remain submerged for long.水冰冷彻骨，他在下面呆不了太长时间。
• She returned his smile with a frigid glance.对他的微笑她报以冷冷的一瞥。

6 astronomical   

adj.天文学的，（数字）极大的

参考例句：

• He was an expert on ancient Chinese astronomical literature.他是研究中国古代天文学文献的专家。
• Houses in the village are selling for astronomical prices.乡村的房价正在飙升。

7 vetting   

n.数据检查[核对，核实]v.审查（某人过去的记录、资格等）( vet的现在分词 )；调查；检查；诊疗

参考例句：

• Scripts had to be submitted to Ministry of Information officials for vetting. 必须把脚本提交给信息部官员审查。 来自互联网
• Their purpose in clicking deeper into a site is one of vetting. 他们深入点击网站的目的是一种诊疗。 来自互联网

8 detailed   

adj.详细的，详尽的，极注意细节的，完全的

参考例句：

• He had made a detailed study of the terrain.他对地形作了缜密的研究。
• A detailed list of our publications is available on request.我们的出版物有一份详细的目录备索。

9 uncertainty   

n.易变，靠不住，不确知，不确定的事物

参考例句：

• Her comments will add to the uncertainty of the situation.她的批评将会使局势更加不稳定。
• After six weeks of uncertainty,the strain was beginning to take its toll.6个星期的忐忑不安后，压力开始产生影响了。

10 density   

n.密集，密度，浓度

参考例句：

• The population density of that country is 685 per square mile.那个国家的人口密度为每平方英里685人。
• The region has a very high population density.该地区的人口密度很高。

11 bodes   

v.预示，预告，预言( bode的第三人称单数 )；等待，停留( bide的过去分词 )；居住；（过去式用bided）等待

参考例句：

• This bodes ill for the failure of the programme. 这是那项计划有凶兆。 来自《现代汉英综合大词典》
• This bodes him no good. 这对他是不祥之兆。 来自《现代英汉综合大词典》

12 hospitable   

adj.好客的；宽容的；有利的，适宜的

参考例句：

• The man is very hospitable.He keeps open house for his friends and fellow-workers.那人十分好客，无论是他的朋友还是同事，他都盛情接待。
• The locals are hospitable and welcoming.当地人热情好客。

13 quiescent   

adj.静止的，不活动的，寂静的

参考例句：

• It is unlikely that such an extremist organization will remain quiescent for long.这种过激的组织是不太可能长期沉默的。
• Great distance in either time or space has wonderful power to lull and render quiescent the human mind.时间和空间上的远距离有一种奇妙的力量，可以使人的心灵平静。

14 scour   

v.搜索；擦，洗，腹泻，冲刷

参考例句：

• Mother made me scour the family silver.母亲让我擦洗家里的银器。
• We scoured the telephone directory for clues.我们仔细查阅电话簿以寻找线索。