美国国家公共电台 NPR Earth's 'Bigger, Older Cousin' Maybe Doesn't Even Exist

Earth's 'Bigger, Older Cousin' Maybe Doesn't Even Exist

AUDIE CORNISH, HOST:

Ever since astronomers² started to detect planets beyond our solar system, they've been trying to find another world just like Earth. A few years ago, they announced that they'd found a planet that was the closest match yet. NPR's Nell Greenfieldboyce reports that scientists have now taken a new look at this discovery and say it may not be what it seemed.

NELL GREENFIELDBOYCE, BYLINE³: It was the summer of 2015, and NASA held a press conference. Its Kepler Space Telescope had detected a new planet named Kepler-452b, and it was big news.

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UNIDENTIFIED REPORTER: The space agency says it has found what it's calling Earth's cousin, the most similar planet to our own they've ever found.

GREENFIELDBOYCE: TV shows and newspapers ran artist depictions of the alien world, and NPR weighed in, of course.

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MELISSA BLOCK, BYLINE: It orbits in the so-called Goldilocks Zone where liquid water, and possibly life, could exist.

GREENFIELDBOYCE: This was the first near-Earth-sized planet orbiting in the habitable zone around a star very similar to our sun. What could be finer? Trouble is now some astronomers say it's not possible to know for sure that this planet actually exists.

FERGAL MULLALLY: There's new information that we can know quantify, which tells us something that we didn't know before.

GREENFIELDBOYCE: Fergal Mullally used to be an astronomer¹ on the Kepler team. He says the original science wasn't shoddy. It's just that researchers have learned more about the telescope's imperfections.

MULLALLY: And I kind of hate saying that because Kepler was an absolutely wonderful instrument. It was exquisite⁴ in the quality the data could detect. But nothing is perfect.

GREENFIELDBOYCE: Kepler stared at stars for years, looking for telltale dips in brightness that meant a planet was passing in front of a star and blocking some of its light. Not every drop in brightness came from a planet, though. Scientists already knew to look for false alarms caused by things like two stars going around each other. But increasingly, researchers have learned that other random⁵ stuff was happening. Maybe a star's brightness naturally varied⁶ or maybe the telescope got hit by a piece of dust. And sometimes this random stuff happened in just the right pattern to mimic⁷ an orbiting planet. So Mullally and some colleagues decided⁸ to go back and take another look at 452-b.

MULLALLY: We've told people there's a planet there. How confident are we actually that there's a planet there now that we're aware of this other noise source and we can sort of characterize it?

GREENFIELDBOYCE: The answer is they are not super confident. What are the chances that this planet is real?

MULLALLY: I would say it's higher than 50 percent and less than 90 percent. That's my gut⁹ feeling on it.

GREENFIELDBOYCE: For a bonafide, confirmed planet, astronomers like to see more like 99 percent certainty, so this is rather awkward. Chris Burke of MIT was on the research team.

CHRIS BURKE: You sort of don't want to be the person to deliver bad news, but sometimes the bad news is the truth of it (laughter).

GREENFIELDBOYCE: He says there's still hope. They're not saying a planet definitely isn't there, and there's other ways to look for it.

BURKE: One possibility that we're looking into is using bigger telescopes, so like the Hubble Space Telescope. Could it be used to independently verify Kepler 452-b?

GREENFIELDBOYCE: Even if it can never be verified, don't be too sad.

BURKE: You know, you can't hear about all of them in the popular press, but there is tons of awesome¹⁰ other planets out there.

GREENFIELDBOYCE: Like Kepler-442b, another world that could be rocky and have temperatures cozy¹¹ enough for life. It orbits a star a little cooler than our sun, so it's not exactly Earth-like, but Burke says that discovery is still reliably confirmed. Nell Greenfieldboyce, NPR News.

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1 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。

2 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》

3 byline   

n.署名；v.署名

参考例句：

• His byline was absent as well.他的署名也不见了。
• We wish to thank the author of this article which carries no byline.我们要感谢这篇文章的那位没有署名的作者。

4 exquisite   

adj.精美的；敏锐的；剧烈的，感觉强烈的

参考例句：

• I was admiring the exquisite workmanship in the mosaic.我当时正在欣赏镶嵌画的精致做工。
• I still remember the exquisite pleasure I experienced in Bali.我依然记得在巴厘岛所经历的那种剧烈的快感。

5 random   

adj.随机的；任意的；n.偶然的(或随便的)行动

参考例句：

• The list is arranged in a random order.名单排列不分先后。
• On random inspection the meat was found to be bad.经抽查，发现肉变质了。

6 varied   

adj.多样的，多变化的

参考例句：

• The forms of art are many and varied.艺术的形式是多种多样的。
• The hotel has a varied programme of nightly entertainment.宾馆有各种晚间娱乐活动。

7 mimic   

v.模仿，戏弄；n.模仿他人言行的人

参考例句：

• A parrot can mimic a person's voice.鹦鹉能学人的声音。
• He used to mimic speech peculiarities of another.他过去总是模仿别人讲话的特点。

8 decided   

adj.决定了的，坚决的；明显的，明确的

参考例句：

• This gave them a decided advantage over their opponents.这使他们比对手具有明显的优势。
• There is a decided difference between British and Chinese way of greeting.英国人和中国人打招呼的方式有很明显的区别。

9 gut   

n.[pl.]胆量；内脏；adj.本能的；vt.取出内脏

参考例句：

• It is not always necessary to gut the fish prior to freezing.冷冻鱼之前并不总是需要先把内脏掏空。
• My immediate gut feeling was to refuse.我本能的直接反应是拒绝。

10 awesome   

adj.令人惊叹的，难得吓人的，很好的

参考例句：

• The church in Ireland has always exercised an awesome power.爱尔兰的教堂一直掌握着令人敬畏的权力。
• That new white convertible is totally awesome.那辆新的白色折篷汽车简直棒极了.

11 cozy   

adj.亲如手足的，密切的，暖和舒服的

参考例句：

• I like blankets because they are cozy.我喜欢毛毯，因为他们是舒适的。
• We spent a cozy evening chatting by the fire.我们在炉火旁聊天度过了一个舒适的晚上。