美国国家公共电台 NPR Astronomers Strike Gravitational Gold In Colliding Neutron Stars

 

MARY LOUISE KELLY, HOST:

For the first time, scientists have seen the violent collision of two neutron¹ stars. They've watched as heavy elements like gold, platinum² and uranium were forged. This cosmic smashup is being hailed as one of the biggest events ever in astrophysics. NPR's Nell Greenfieldboyce reports.

NELL GREENFIELDBOYCE, BYLINE³: On the morning of August 17, David Shoemaker was sitting in a boring meeting when he got an alert.

DAVID SHOEMAKER: A phone alarm went off in my pocket that said something interesting has happened.

GREENFIELDBOYCE: David Shoemaker is a physicist⁴ at MIT who studies gravitational waves. Those are ripples⁵ in the fabric⁶ of space-time that are created when something big in the universe goes boom. His phone had buzzed because some of those waves had been picked up by two giant detectors⁷. What's more, just as the waves arrived, an orbiting NASA satellite saw a pulse of high-energy light.

SHOEMAKER: And that put us into a very high state of excitement.

GREENFIELDBOYCE: The detectors Shoemaker works on are called LIGO. In the past, LIGO has picked up waves created by two black holes colliding. But that kind of crash doesn't generate any light, so this was something new. The LIGO researchers sent out a bulletin to astronomers⁸ all over the world telling them where to point their telescopes. Benjamin Shappee with the University of Hawaii was in Chile. He and his colleagues had to wait for sunset. But once it got dark, the team almost immediately found it - a new spot of light in the sky.

BENJAMIN SHAPPEE: It just felt - to me at the time, I was like, this is almost too easy. It was, like, almost too perfect.

GREENFIELDBOYCE: The little circle of light started out bright and blue. Over the next few days, it faded and became redder as scientists around the world watched with awe⁹. What they were seeing was the fiery¹⁰ collision of two neutron stars 130 million light-years away. Neutron stars are stars but weird¹¹ ones.

EDO BERGER: Each one is about the size of a city like Boston or New York or Seattle but weighing more than the mass of the sun.

GREENFIELDBOYCE: Edo Berger is an astrophysicist at Harvard. He says when two circling neutron stars finally collide, they're going fast - about a third of the speed of light.

BERGER: So it's this amazing, powerful head-on collision between these two extremely dense¹² objects, I think one of the most extreme events one could imagine in space.

GREENFIELDBOYCE: And it used to be that imagining was all anyone could do. Daniel Kasen is a theoretical astrophysicist at the University of California, Berkeley. He spent years thinking about colliding neutron stars, so watching this unfold was uncanny.

DANIEL KASEN: Even though this was an event that had never been seen before in human history, what it looked like was, you know, deeply familiar because it resembled very closely to the predictions that we had been making.

GREENFIELDBOYCE: And seeing this solved a longstanding mystery in astrophysics. Where do heavy elements like gold and platinum come from? Kasen says this neutron star collision created a cloud of radioactive waste the size of our solar system filled with an astonishing haul of precious metal.

KASEN: We estimate that there's maybe, you know, upwards¹³ of 200 Earth masses of pure gold in this cloud and probably even more platinum - maybe 500 Earth masses worth. Today, major science journals published a bunch of reports on all these observations authored by more than 3,000 researchers. One of them is Peter Saulson of Syracuse University.

PETER SAULSON: It's so beautiful. It's so beautiful. It makes me want to cry.

GREENFIELDBOYCE: He says this is not just the fulfillment of thousands of people's efforts.

SAULSON: But it's also the fulfillment of, you know, an idea suddenly becoming real.

GREENFIELDBOYCE: It was Albert Einstein over a century ago who predicted that gravitational waves should exist. The work that led to the first detections won the Nobel Prize earlier this month. And as this latest discovery shows, scientists now have a powerful new way to see the most extreme events in the universe. Nell Greenfieldboyce, NPR News.

(SOUNDBITE OF OK IKUMI'S "HEIGHTS")

1 neutron   

n.中子

参考例句：

• Neutron is neutral and slightly heavier than the proton.中子是中性的，比质子略重。
• Based on the neutron energy,the value of weighting factor was given.根据中子能量给出了相应的辐射权重因子的数值。

2 platinum   

n.白金

参考例句：

• I'll give her a platinum ring.我打算送给她一枚白金戒指。
• Platinum exceeds gold in value.白金的价值高于黄金。

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 physicist   

n.物理学家，研究物理学的人

参考例句：

• He is a physicist of the first rank.他是一流的物理学家。
• The successful physicist never puts on airs.这位卓有成就的物理学家从不摆架子。

5 ripples   

逐渐扩散的感觉( ripple的名词复数 )

参考例句：

• The moon danced on the ripples. 月亮在涟漪上舞动。
• The sea leaves ripples on the sand. 海水在沙滩上留下了波痕。

6 fabric   

n.织物，织品，布；构造，结构，组织

参考例句：

• The fabric will spot easily.这种织品很容易玷污。
• I don't like the pattern on the fabric.我不喜欢那块布料上的图案。

7 detectors   

探测器( detector的名词复数 )

参考例句：

• The report advocated that all buildings be fitted with smoke detectors. 报告主张所有的建筑物都应安装烟火探测器。
• This is heady wine for experimenters using these neutrino detectors. 对于使用中微子探测器的实验工作者，这是令人兴奋的美酒。 来自英汉非文学 - 科技

8 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》

9 awe   

n.敬畏，惊惧；vt.使敬畏，使惊惧

参考例句：

• The sight filled us with awe.这景色使我们大为惊叹。
• The approaching tornado struck awe in our hearts.正在逼近的龙卷风使我们惊恐万分。

10 fiery   

adj.燃烧着的，火红的；暴躁的；激烈的

参考例句：

• She has fiery red hair.她有一头火红的头发。
• His fiery speech agitated the crowd.他热情洋溢的讲话激动了群众。

11 weird   

adj.古怪的，离奇的；怪诞的，神秘而可怕的

参考例句：

• From his weird behaviour,he seems a bit of an oddity.从他不寻常的行为看来，他好像有点怪。
• His weird clothes really gas me.他的怪衣裳简直笑死人。

12 dense   

a.密集的，稠密的，浓密的；密度大的

参考例句：

• The general ambushed his troops in the dense woods. 将军把部队埋伏在浓密的树林里。
• The path was completely covered by the dense foliage. 小路被树叶厚厚地盖了一层。

13 upwards   

adv.向上，在更高处...以上

参考例句：

• The trend of prices is still upwards.物价的趋向是仍在上涨。
• The smoke rose straight upwards.烟一直向上升。