美国国家公共电台 NPR Massive U.S. Machines That Hunt For Ripples In Space-Time Just Got An Upgrade

 

RACHEL MARTIN, HOST:

Albert Einstein predicted that some cosmic smashups would be so powerful, they'd create ripples¹ in the very fabric² of the universe. A century later, physicists⁴ proved him right when they detected the ripples created by the collision of two black holes. The massive detectors⁶ used to make that discovery have now gotten an upgrade, and they are just about to start back up. NPR's Nell Greenfieldboyce reports.

NELL GREENFIELDBOYCE, BYLINE⁷: Gabby Gonzalez is a physicist³ at Louisiana State University who has spent years, decades, working with a team that was trying to detect something that had never been detected before.

GABRIELA GONZALEZ: I have lots of friends that, now, they tell me, I felt so worried about your career because you were working on such a difficult thing that I thought it was never going to happen. And now, I'm so jealous (laughter).

GREENFIELDBOYCE: They're jealous because in 2015, it did happen - the first-ever detection of gravitational waves. You can't see them. You can't feel them. But Albert Einstein had it right. Space and time is a kind of jiggly matrix. And when two big things out in the universe collide, they can send shockwaves through spacetime that are like the ripples you make when you toss a pebble⁸ into a pond. Being able to sense these waves is brand new for astronomy, which has spent centuries studying light.

GONZALEZ: Galileo invented the telescope or used the telescope for the first time to do astronomy 400 years ago. And today, we're still building better telescopes. I think this decade has been the beginning of gravitational wave astronomy.

GREENFIELDBOYCE: And she thinks it should just keep getting better and better. The United States has two facilities for detecting gravitational waves - one in Washington state and one in Louisiana. Together, they're called LIGO for the Laser Interferometer Gravitational-Wave Observatory⁹. I drove about an hour and a half north of New Orleans to see the one in rural Louisiana. The head of the observatory, Joe Giaime, took me over to a display case to see a gold medal.

JOSEPH GIAIME: People who win Nobel prizes can pay a little extra money, and check a box and get a duplicate.

GREENFIELDBOYCE: Each site has one of these since the first detection of gravitational waves was such a big deal that the Nobel Committee, pretty much instantly, honored three American physicists for their work on this project. We walk out onto a bridge that goes over a big concrete pipe. From here, we see the pipe going off into the distance, and we can also see another pipe as well. Giaime says each is more than two miles long. They come together in a shape that, from above, looks like a capital L.

GIAIME: I've spoken with pilots who fly over this. And they wonder why there's a pipeline¹⁰ that starts nowhere, travels, you know, a couple miles, turns right and then goes also nowhere.

GREENFIELDBOYCE: Inside each stretch of pipe is a powerful laser beam that bounces back and forth¹¹ between mirrors. Scientists use this laser to precisely¹² measure the length of each arm of the L. When a gravitational wave passes through and distorts space, the lengths change by a tiny, tiny bit like a fraction of the width of a subatomic particle.

GIAIME: We're in the control room now, and this is where all of the activities of both the site and the detector⁵ are monitored and controlled.

GREENFIELDBOYCE: It's a windowless room with people sitting at dozens of computer monitors. Since the first historic detection 3 1/2 years ago, this place has registered 10 more gravitational wave events. Nine were black hole collisions, and one was a pair of neutron¹³ stars smashing together. But the science has been shut down for more than a year. That was to let researchers install new hardware and other upgrades. The workers in here, now, are testing them out. On April 1, everything officially comes back online. Giaime says the U.S. detectors plus another one in Italy will all be more sensitive.

GIAIME: So, so far, we've seen 11 things. Maybe we'll see twice that many this year.

GREENFIELDBOYCE: And they'll be better able to locate the source of the waves in the sky. The team will send out public alerts so that anyone can point their telescopes at the right spot. In case, like the neutron star collision, the event sends out cosmic fireworks. Thousands of astronomers¹⁴ and physicists around the world are now involved in studying gravitational waves because these offer the only way to explore some of the most powerful, exotic events in the universe. And that's the fun of it. Nergis Mavalvala is a physicist at MIT.

NERGIS MAVALVALA: We've only seen this handful of black holes of all the possible ones that are out there. There are many, many questions we still don't know how to answer.

GREENFIELDBOYCE: Plus, maybe something completely unexpected will go boom.

MAVALVALA: That's how discovery happens. As you turn on a new instrument, you point it out at the sky and you see something that you had no idea existed.

GREENFIELDBOYCE: She says that's happened time and time again in astronomy, and she bets it'll happen for gravitational waves as well. Nell Greenfieldboyce, NPR News.

1 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。

2 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。

3 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。

4 physicists   

物理学家( physicist的名词复数 )

参考例句：

• For many particle physicists, however, it was a year of frustration. 对于许多粒子物理学家来说，这是受挫折的一年。 来自英汉非文学 - 科技
• Physicists seek rules or patterns to provide a framework. 物理学家寻求用法则或图式来构成一个框架。

5 detector   

n.发觉者，探测器

参考例句：

• The detector is housed in a streamlined cylindrical container.探测器安装在流线型圆柱形容器内。
• Please walk through the metal detector.请走过金属检测器。

6 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

7 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。

8 pebble   

n.卵石，小圆石

参考例句：

• The bird mistook the pebble for egg and tried to hatch it.这只鸟错把卵石当蛋，想去孵它。
• The pebble made a ripple on the surface of the lake.石子在湖面上激起一个涟漪。

9 observatory   

n.天文台，气象台，瞭望台，观测台

参考例句：

• Guy's house was close to the observatory.盖伊的房子离天文台很近。
• Officials from Greenwich Observatory have the clock checked twice a day.格林威治天文台的职员们每天对大钟检查两次。

10 pipeline   

n.管道，管线

参考例句：

• The pipeline supplies Jordan with 15 per cent of its crude oil.该管道供给约旦15%的原油。
• A single pipeline serves all the houses with water.一条单管路给所有的房子供水。

11 forth   

adv.向前；向外，往外

参考例句：

• The wind moved the trees gently back and forth.风吹得树轻轻地来回摇晃。
• He gave forth a series of works in rapid succession.他很快连续发表了一系列的作品。

12 precisely   

adv.恰好，正好，精确地，细致地

参考例句：

• It's precisely that sort of slick sales-talk that I mistrust.我不相信的正是那种油腔滑调的推销宣传。
• The man adjusted very precisely.那个人调得很准。

13 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。

14 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》