Scientists Plan to Make 3-D Map of the Milky Way 科学家计划制作银河系的3d地图

 

Scientists Plan to Make 3-D Map of the Milky¹ Way 科学家计划制作银河系的3d地图

From VOA Learning English, this is Science in the News.  I’m June Simms.

And I’m Jim Tedder².  Today on the program, we tell about developments in space exploration.  We tell about an American decision to extend the life of the International Space Station.  We also tell about the American space agency’s Mars rover Opportunity and new findings from the red planet.  We have a report about what appear to be high energy particles from outside our solar system.  But first, we report on plans for an unusual map. 

A man-made satellite called Gaia started a long trip late last year.  The satellite was designed to travel more than a million kilometers from Earth.  Scientists are hoping that Gaia will take pictures of our galaxy³, the Milky Way.  They plan to use the pictures to create the first three-dimensional -- or 3-D -- map of the Milky Way.  It will show the height, depth and width of stars and other large, recognizable objects.

The satellite weighs two tons.  It was launched on a Russian Soyuz rocket last December from the European Space Agency’s center in French Guiana.  Gaia rose quickly and soon began orbiting the Earth.  It then deployed⁴ a 10-meter-large circular sunshield.  The device is keeping instruments on the satellite -- including two telescopes – cool on the long trip. 

The scientists hope to use the telescope to study distant stars.  Gaia was designed to be mechanically stable.  That is why the satellite has so few moving parts.  In addition, its temperature must not change very much. 

Mark McCaughrean is the chief scientist for the Gaia mission.  He says the information Gaia gathers will help scientists understand how our galaxy developed, how it looks today, and how it may change.

“It will measure the positions of a billion stars but also their speeds, their motions.  And with that we can run a movie of the Milky Way.  We can run it forwards, into the future, how the Milky Way will develop by looking at all the stars and how they move.  But we can run it backwards⁵ as well, and we can see how the Milky Way actually formed in the first place.”

Gerard F. Gilmore is with the Institute of Astronomy at England’s Cambridge University.  He says the 3-D images will one day show half of the Milky Way.  He says the map will provide new knowledge about what keeps the galaxy together.

“And the particular interest that I have in here, locally, is in the nature of dark matter.  What is dark matter made of?  Dark matter is most of the weight in the Milky Way.  It is dark matter that holds the Milky Way together.  If there weren’t all this dark material, our sun would fly off away from the galaxy.  The whole galaxy would fall apart.”

Scientists expect the satellite to operate for five years in an area about 1.5 million kilometers from Earth.  It will take about 70 pictures of each of the one billion stars in the Milky Way.  The mission is expected to cost about $1.3 billion.

The United States’ space agency has announced plans to keep the International Space Station operating until 2024.  The $100 billion space station has already been in service for 15 years.  It was supposed to halt operations in 2020. 

The space agency and the Obama administration say extending the life of the space station will help the US and its international partners meet several goals.  These include scientific research and giving private businesses time to fully⁶ take responsibility for transporting shipments and crew to low-Earth orbit.

One of the private companies is Orbital Sciences Corporation.  It sent a supply flight to the space station in early January.  The space agency retired⁷ the last of its space shuttles in 2011.  Since then, it has been using Orbital Sciences and another company -- SpaceX -- to transport supplies to the space station.  It has also been getting support from Russia.  Flight crews are brought to the space station on Russian Soyuz spacecraft.

More Opportunities for Scientific Study on Mars

The US space agency says its Mars rover vehicle “Opportunity” is still working more than 10 years after arriving on the red planet.  Opportunity landed on Mars on January 24, 2004 -- several weeks after another rover vehicle, called “Spirit.” 

NASA, the National Aeronautics⁸ and Space Administration, says one of Opportunity’s six wheels and two instruments stopped working long ago.  But those are minor⁹ problems when you think about how long the project was supposed to last: just three months.  Spirit stopped sending signals in 2010 after getting stuck in sand.

Opportunity has travelled about 39 kilometers on the planet’s surface.  NASA scientists say the rover continues making new discoveries.  It recently overturned a rock, so that its bottom was exposed to the Martian atmosphere for the first time in perhaps billions of years. 

Early discoveries by the two rovers showed the planet may have at one time been much warmer and wet.  And recently, Opportunity found geologic¹¹ evidence of water in an area called the Endeavour Crater¹².  Scientists believe the discovery could help them find places other than the Earth where simple life forms could have survived.

New research shows mineral-eating organisms could have lived on Mars.  Scientists say this is the best evidence yet that the planet could once have supported life forms.

Last year, scientists reported evidence of water on Mars.  In the latest research, the Mars rover vehicle “Curiosity” found two minerals -- iron and sulfur¹³ -- in different chemical states at the bottom of a former lake.  The finding is important because the different states suggest that electrons could move around in that environment.  Scott McLennan is a professor of geoscience at Stony¹⁴ Brook¹⁵ University in New York.  

“If you can move electrons around you have basically got food.”

Professor McLennan is part of the Mars rover team that made the discovery.

“In principle, you would have microbes that could eat the rocks and eat the minerals.  And that is very common on Earth.  They are primitive¹⁶ life forms but they are very, very well-known and very well-characterized.”

Such life forms are found in dark caves and deep-sea thermal¹⁷ vents¹⁸ on Earth.  These areas do not get the sunlight that is the root of all life on our planet’s surface.

Hap¹⁰ McSween is a planetary science professor at the University of Tennessee.  He says recent research papers claimed there could be life on Mars.  But he says this was the first time he has been persuaded of it.

Professor McSween was not involved in the recent study.  He says it is not the first time researchers have found water or important minerals on Mars.

“But never the whole package.  And this place really does seem to have the whole package.”

The materials were found near the place where Curiosity landed.  The area appears to have been a lake about four billion years ago.  Professor McSween notes that was around the time life was appearing on Earth.

“It could be that the two planets had emerging but very, very simplified life at the same time.  But we are a long way from figuring out that this interesting lake deposit actually has any evidence for life.”

Sensing equipment buried deep in the Antarctic ice has found evidence of high energy particles from outside our solar system. 

IceCube is the name of a device operating in Antarctica.  It has more than 5,000 light sensors¹⁹ buried as deep as two kilometers below the surface.  IceCube has been called, the world’s largest particle detector²⁰ searching for “neutrinos”. 

Neutrinos are unimaginably small particles.  They travel from the sun or Earth’s own atmosphere at near light speed.  Billions of them pass through us every second.  But these are low energy neutrinos.  They are not what interest the 250 scientists from 11 countries working with information from IceCube. 

Francis Halzen is the lead investigator²¹ on the project and a physics professor at the University of Wisconsin.   He says IceCube is looking in the ice for high-energy neutrinos from outside the solar system.   

“What we want to see is a handful of events sent to us by the universe.  We’ve finally discovered those.” 

When the neutrinos mix with atoms inside the deep ice instrumentss, they sometimes give off small amounts of light.  In 2010, scientists discovered two high-energy neutrinos.  Two years later, they found 26 more -- including the most-energetic neutrinos ever observed.

Nathan Whitehorn is a physicist²² at the University of Wisconsin.  He also is working on the IceCube project.  He says the discovery of the 26 neutrinos after finding the first two was very important. 

“It was almost impossible, without more data and data at lower energies, to be sure that these two neutrinos that we found were part of a larger pattern indicating an extraterrestrial population, instead of some statistical²³ fluke.” 

Neutrinos have almost no mass or weight, and no electric charge.  That is why the Earth’s magnetic fields have no effect on them.  Neutrinos move quickly and in a straight line through the solar system.  That movement is very different from electrically-charged cosmic rays.  Professor Whitehorn says the lack of an electric charge in neutrinos means they can help scientists find where cosmic rays came from.

“We expect that anything that is making high-energy cosmic rays -- the most energetic phenomenon in the universe -- whatever they are, will make neutrinos at the same time and if we are able to identify the origin of these high-energy neutrinos, they will provide some very powerful clues about the origin of the highest-energy cosmic rays.”

Scientists have been attempting to solve this mystery for more than a century.  They hope these extraterrestrial messengers will help them do that.

 

This Science in the News was written and produced by Christopher Cruise.  I’m Jim Tedder.

1 milky   

adj.牛奶的，多奶的；乳白色的

参考例句：

• Alexander always has milky coffee at lunchtime.亚历山大总是在午餐时喝掺奶的咖啡。
• I like a hot milky drink at bedtime.我喜欢睡前喝杯热奶饮料。

2 tedder   

n.（干草）翻晒者，翻晒机

参考例句：

• Jim Tedder has more. 吉姆？特德将给我们做更多的介绍。 来自互联网
• Jim Tedder tells us more. 吉姆？泰德给我们带来更详细的报道。 来自互联网

3 galaxy   

n.星系；银河系；一群(杰出或著名的人物)

参考例句：

• The earth is one of the planets in the Galaxy.地球是银河系中的星球之一。
• The company has a galaxy of talent.该公司拥有一批优秀的人才。

4 deployed   

（尤指军事行动）使展开( deploy的过去式和过去分词 )； 施展； 部署； 有效地利用

参考例句：

• Tanks have been deployed all along the front line. 沿整个前线已部署了坦克。
• The artillery was deployed to bear on the fort. 火炮是对着那个碉堡部署的。

5 backwards   

adv.往回地，向原处，倒，相反，前后倒置地

参考例句：

• He turned on the light and began to pace backwards and forwards.他打开电灯并开始走来走去。
• All the girls fell over backwards to get the party ready.姑娘们迫不及待地为聚会做准备。

6 fully   

adv.完全地，全部地，彻底地；充分地

参考例句：

• The doctor asked me to breathe in,then to breathe out fully.医生让我先吸气，然后全部呼出。
• They soon became fully integrated into the local community.他们很快就完全融入了当地人的圈子。

7 retired   

adj.隐退的，退休的，退役的

参考例句：

• The old man retired to the country for rest.这位老人下乡休息去了。
• Many retired people take up gardening as a hobby.许多退休的人都以从事园艺为嗜好。

8 aeronautics   

n.航空术，航空学

参考例句：

• National Aeronautics and Space undertakings have made great progress.国家的航空航天事业有了很大的发展。
• He devoted every spare moment to aeronautics.他把他所有多余的时间用在航空学上。

9 minor   

adj.较小(少)的，较次要的；n.辅修学科；vi.辅修

参考例句：

• The young actor was given a minor part in the new play.年轻的男演员在这出新戏里被分派担任一个小角色。
• I gave him a minor share of my wealth.我把小部分财产给了他。

10 hap   

n.运气；v.偶然发生

参考例句：

• Some have the hap,some stick in the gap.有的人走运, 有的人倒霉。
• May your son be blessed by hap and happiness.愿你儿子走运幸福。

11 geologic   

adj.地质的

参考例句：

• The Red Sea is a geologic continuation of the valley.红海就是一个峡谷在地质上的继续发展。
• Delineation of channels is the first step of geologic evaluation.勾划河道的轮廓是地质解译的第一步。

12 crater   

n.火山口，弹坑

参考例句：

• With a telescope you can see the huge crater of Ve-suvius.用望远镜你能看到巨大的维苏威火山口。
• They came to the lip of a dead crater.他们来到了一个死火山口。

13 sulfur   

n.硫，硫磺（=sulphur）

参考例句：

• Sulfur emissions from steel mills become acid rain.炼钢厂排放出的硫形成了酸雨。
• Burning may produce sulfur oxides.燃烧可能会产生硫氧化物。

14 stony   

adj.石头的，多石头的，冷酷的，无情的

参考例句：

• The ground is too dry and stony.这块地太干，而且布满了石头。
• He listened to her story with a stony expression.他带着冷漠的表情听她讲经历。

15 brook   

n.小河，溪；v.忍受，容让

参考例句：

• In our room we could hear the murmur of a distant brook.在我们房间能听到远处小溪汩汩的流水声。
• The brook trickled through the valley.小溪涓涓流过峡谷。

16 primitive   

adj.原始的；简单的；n.原(始)人，原始事物

参考例句：

• It is a primitive instinct to flee a place of danger.逃离危险的地方是一种原始本能。
• His book describes the march of the civilization of a primitive society.他的著作描述了一个原始社会的开化过程。

17 thermal   

adj.热的，由热造成的；保暖的

参考例句：

• They will build another thermal power station.他们要另外建一座热能发电站。
• Volcanic activity has created thermal springs and boiling mud pools.火山活动产生了温泉和沸腾的泥浆池。

18 vents   

（气体、液体等进出的）孔、口( vent的名词复数 )； （鸟、鱼、爬行动物或小哺乳动物的）肛门； 大衣等的)衩口； 开衩

参考例句：

• He always vents his anger on the dog. 他总是拿狗出气。
• The Dandelion Patch is the least developed of the four active vents. “蒲公英区”在这四个活裂口中是发育最差的一个。

19 sensors   

n.传感器，灵敏元件( sensor的名词复数 )

参考例句：

• There were more than 2000 sensors here. 这里装有两千多个灵敏元件。 来自《简明英汉词典》
• Significant changes have been noted where sensors were exposed to trichloride. 当传感器暴露在三氯化物中时，有很大变化。 来自辞典例句

20 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。

21 investigator   

n.研究者，调查者，审查者

参考例句：

• He was a special investigator for the FBI.他是联邦调查局的特别调查员。
• The investigator was able to deduce the crime and find the criminal.调查者能够推出犯罪过程并锁定罪犯。

22 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。

23 statistical   

adj.统计的，统计学的

参考例句：

• He showed the price fluctuations in a statistical table.他用统计表显示价格的波动。
• They're making detailed statistical analysis.他们正在做具体的统计分析。