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[阅读小分队] 【每日阅读训练第四期——速度越障20系列】【20-07】科技

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发表于 2013-6-10 21:31:09 | 显示全部楼层 |阅读模式
队友们集合,周二的科技来了,大家列队做阅读练习啦~

今天的关键词跟天体、宇宙、地球。。。越障有俩选项,大家选一个做就好。都是NASA 6月的新闻。下周弄些生物化学类的,嘿嘿~

加油!

Part I Speed

Article I
Stars Don't Obliterate Their Planets (Very Often)

【Warm up】
Researchers using data from NASA's Kepler space telescope have shown that migrating planets stop their inward journey before reaching their stars, as illustrated in this artist's concept. Jupiter-like planets, called "hot Jupiters" are known to migrate from their star's frigid outer reaches in toward the star and its blistering heat. Dozens of hot Jupiters have been discovered orbiting closely to their stars, whipping around in just days.

Until now, it was not clear whether these massive planets remain in stable orbits close to their stars or keep marching in closer and closer until they are ultimately consumed. The new work not only demonstrates that the planets stop their migration inward, but also shows how.

The tidal, or gravitational, forces acting to circularize the orbits of the planets cause them to cease their inbound travels once they have hit the stable orbits.
【141words】

【Time1】
Stars have an alluring pull on planets, especially those in a class called hot Jupiters, which are gas giants that form farther from their stars before migrating inward and heating up.

Now, a new study using data from NASA's Kepler Space Telescope shows that hot Jupiters, despite their close-in orbits, are not regularly consumed by their stars. Instead, the planets remain in fairly stable orbits for billions of years, until the day comes when they may ultimately get eaten.

"Eventually, all hot Jupiters get closer and closer to their stars, but in this study we are showing that this process stops before the stars get too close," said Peter Plavchan of NASA's Exoplanet Science Institute at the California Institute of Technology, Pasadena, Calif. "The planets mostly stabilize once their orbits become circular, whipping around their stars every few days."

The study, published recently in the Astrophysical Journal, is the first to demonstrate how the hot Jupiter planets halt their inward march on stars. Gravitational, or tidal, forces of a star circularize and stabilize a planet's orbit; when its orbit finally become circular, the migration ceases.

"When only a few hot Jupiters were known, several models could explain the observations," said Jack Lissauer, a Kepler scientist at NASA's Ames Research Center, Moffet Field, Calif., not affiliated with the study. "But finding trends in populations of these planets shows that tides, in combination with gravitational forces by often unseen planetary and stellar companions, can bring these giant planets close to their host stars."
【251words】

【Time2】
Hot Jupiters are giant balls of gas that resemble Jupiter in mass and composition. They don't begin life under the glare of a sun, but form in the chilly outer reaches, as Jupiter did in our solar system. Ultimately, the hot Jupiter planets head in toward their stars, a relatively rare process still poorly understood.

The new study answers questions about the end of the hot Jupiters' travels, revealing what put the brakes on their migration. Previously, there were a handful of theories explaining how this might occur. One theory proposed that the star's magnetic field prevented the planets from going any farther. When a star is young, a planet-forming disk of material surrounds it. The material falls into the star -- a process astronomers call accretion -- but when it hits the magnetic bubble around it, called the magnetosphere, the material travels up and around the bubble, landing on the star from the top and bottom. This bubble could be halting migrating planets, so the theory went.

Another theory held that the planets stopped marching forward when they hit the end of the dusty portion of the planet-forming disk.

"This theory basically said that the dust road a planet travels on ends before the planet falls all the way into the star," said co-author Chris Bilinski of the University of Arizona, Tucson. "A gap forms between the star and the inner edge of its dusty disk where the planets are thought to stop their migration."

And yet a third theory, the one the researchers found to be correct, proposed that a migrating planet stops once the star's tidal forces have completed their job of circularizing its orbit.

To test these and other scenarios, the scientists looked at 126 confirmed planets and more than 2,300 candidates. The majority of the candidates and some of the known planets were identified via NASA's Kepler mission. Kepler has found planets of all sizes and types, including rocky ones that orbit where temperatures are warm enough for liquid water.
【335words】

【Time3】
The scientists looked at how the planets' distance from their stars varied depending on the mass of the star. It turns out that the various theories explaining what stops migrating planets differ in their predictions of how the mass of a star affects the orbit of the planet. The "tidal forces" theory predicted that the hot Jupiters of more massive stars would orbit farther out, on average.

The survey results matched the "tidal forces" theory and even showed more of a correlation between massive stars and farther-out orbits than predicted.

This may be the end of the road for the mystery of what halts migrating planets, but the journey itself still poses many questions. As gas giants voyage inward, it is thought that they sometimes kick smaller, rocky planets out of the way, and with them any chance of life evolving. Lucky for us, our Jupiter did not voyage toward the sun, and our Earth was left in peace. More studies like this one will help explain these and other secrets of planetary migration.

NASA Ames manages Kepler's ground system development, mission operations and science data analysis. NASA's Jet Propulsion Laboratory in Pasadena, Calif., managed Kepler mission development. Ball Aerospace & Technologies Corp. in Boulder, Colo., developed the Kepler flight system and supports mission operations with JPL at the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder. The Space Telescope Science Institute in Baltimore archives, hosts and distributes the Kepler science data. Kepler is NASA's 10th Discovery Mission and is funded by NASA's Science Mission Directorate at the agency's headquarters in Washington.
【267words】

Article II
Hubble Maps 3-D Structure of Ejected Material Around Erupting Star

【Warm up】
Hubble's Wide Field Camera 3 imaged the double-star system T Pyxidis, or T Pyx, over a four-month period. T Pyx is a recurrent nova, erupting every 12 to 50 years. T Pyx's latest outburst was in April 2011. The star is the white blob in the middle of each image。
【50words】

【Time4】
A flash of light from a stellar outburst has provided a rare look at the 3-D structure of material ejected by an erupting nova.

Astronomers used NASA's Hubble Space Telescope to observe the light emitted by the close double-star system T Pyxidis, or T Pyx, a recurring nova, during its latest outburst in April 2011.

A nova erupts when a white dwarf, the burned-out core of a sun-like star, has siphoned off enough hydrogen from a companion star to trigger a thermonuclear runaway. As hydrogen builds up on the surface of the white dwarf, it becomes hotter and denser until it detonates like a colossal hydrogen bomb, leading to a 10,000-fold increase in brightness in a little more than one day. Nova explosions are extremely powerful, equal to a blast of one million billion tons of dynamite. T Pyx erupts every 12 to 50 years.

Contrary to some predictions, the astronomers were surprised to find the ejecta from earlier outbursts stayed in the vicinity of the star and formed a disk of debris around the nova. The discovery suggests material continues expanding outward along the system's orbital plane, but it does not escape the system.

"We fully expected this to be a spherical shell," says Arlin Crotts of Columbia University, a member of the research team. "This observation shows it is a disk, and it is populated with fast-moving ejecta from previous outbursts."

Team member Stephen Lawrence of Hofstra University in Hempstead, N.Y., will present the results Tuesday at the American Astronomical Society meeting in Indianapolis.

Team member Jennifer Sokoloski, also of Columbia University and co-investigator on the project, suggests these data indicate the companion star plays an important role in shaping how material is ejected, presumably along the system's orbital plane, creating the pancake-shaped disk. The disk is tilted about 30 degrees from face-on toward Earth.
【307words】

【Time5】
Using Hubble's Wide Field Camera 3, the team took advantage of the blast of light emitted by the erupting nova to trace the light's path as it lit up the disk and material from previous ejecta. The disk is so vast, about a light-year across, that the nova's light cannot illuminate all of the material at once. Instead, the light sweeps across the material, sequentially illuminating parts of the disk, a phenomenon called a light echo. The light reveals which parts of the disk are nearer to Earth and which sections are farther away. By tracing the light, the team assembled a 3-D map of the structure around the nova.

"We've all seen how light from fireworks shells during the grand finale will light up the smoke and soot from shells earlier in the show," Lawrence said. "In an analogous way, we're using light from T Pyx's latest outburst and its propagation at the speed of light to dissect its fireworks displays from decades past."

Although astronomers have witnessed light propagating through material surrounding other novae, this is the first time the immediate environment around an erupting star has been studied in three dimensions.

Astronomers have studied light echoes from other novae, but those phenomena illuminated interstellar material around the stars instead of material ejected from them.

The team also used the light echo to refine estimates of the nova's distance from Earth. The new distance is 15,600 light-years from Earth. Previous estimates were between 6,500 and 16,000 light-years. T Pyx is located in the southern constellation Pyxis, or the Mariner's Compass.

The team is continuing to analyze the Hubble data to develop an outflow model. T Pyx has a history of outbursts. Besides the 2011 event, other previous known eruptions were seen in 1890, 1902, 1920, 1944, and 1966.

Astronomers call erupting stars novae, Latin for "new," because they abruptly appear in the sky. A nova quickly begins to fade in several days or weeks as the hydrogen is exhausted and blown into space.

The team also includes Helena Uthas of Columbia University. The team's results will appear online June 5 and will be published in the June 20, 2013, issue of the Astrophysical Journal Letters. Sokoloski is the paper's lead author.
【373words】

Part II Obstacle
Article III (OptionA)
Listening for the Boom and Rattle of Supersonic Flight

【Time6】
It looks like a living room you might find almost anywhere -- an 11 by 13 foot space with eight-foot ceilings (3.4 x 4.0 x 2.4 meters) that contains a couch, chair, TV, coffee table and more. But this is no living room -- it is a noise test chamber called the Interior Effects Room at NASA's Langley Research Center in Hampton, Va.

Acoustics researchers had it constructed so they could assess people's perceptions of noise. Some noises are more annoying to people than others, according to research aerospace engineer Alexandra Loubeau. "That includes loud or startling things that make you have this sort of fear reaction -- you think there's danger because there's a really loud sound," she said. "Most people are most annoyed by those sounds."

But why do NASA engineers care about sound? Loubeau and her colleagues are "hoping to change the future air transportation system across the world."

One thing that is affecting the growth of air traffic and the kind of planes being built is noise -- noise created by airplane structures and engines, noise in the community and the noise created by sonic booms. For a recent test NASA Langley researchers invited 33 people from the community to sit in the Interior Effects Room and listen to boom and rattle sounds similar to those caused by a plane flying at supersonic speeds. The test is part of NASA's research efforts to determine at what levels a sonic boom would be "acceptable" to members of the public.

"For this test we created synthesized sonic booms based on designs for future supersonic aircraft," said research aerospace engineer Jonathan Rathsam. "The rattle noises, however, were recorded by ourselves and by our colleagues, thumping on doors and pulling back ceiling fan blades to create noises that really would be associated with household items that might be affected by a sonic boom."

Those sounds are transmitted by 52 subwoofers and 52 mid-range speakers embedded in the walls and seven satellite speakers and a subwoofer in the room. Researchers sit in a control room and watch as test subjects use computers to record how annoying they perceive the noise to be.

Each test includes 207 sounds. But researchers take all appropriate precautions to make sure those noises don't hurt the listeners' hearing. A Langley review board evaluates and approves all tests to ensure the safety of subjects. Also before and after each test the subjects undergo a standard hearing measurement assessment to document that their hearing hasn't changed during the hour-long test.

"While we are running the test we also have what we call a limiter system," said Loubeau. "It's monitoring the sounds in the room throughout the whole test. If something were to go wrong and a noise went above 95 decibels (slightly louder than a lawnmower) this limiter system detects that and automatically shuts off all the amplifiers for the subwoofers and all our speakers."

The Interior Effects Room Boom and Rattle Study is part of the NASA High Speed Project's ongoing efforts to develop technologies to advance supersonic passenger travel. "The point of the test is for us to develop a capability to predict the annoyance caused by these sounds in the population," said Rathsam. "Right now supersonic flight is forbidden over land because conventional booms are annoying to communities on the ground. This predictive model will be used by aircraft designers to determine how much a particular design is likely to annoy listeners on the ground and aircraft noise regulators to develop a metric to regulate what might be an acceptable level for sonic boom."

The noise tests in the lab complement flight tests done at NASA's Dryden Flight Research Center at Edwards Air Force Base, Calif., to try to give researchers a complete picture of sonic boom noise and the best way to quantify it so that supersonic passenger travel might some day become commonplace.
【650words】

Article IV (OptionB)
Noctilucent Clouds Get an Early Start

【Time7】
Every summer, something strange and wonderful happens high above the north pole. Ice crystals begin to cling to the smoky remains of meteors, forming electric-blue clouds with tendrils that ripple hypnotically against the sunset sky. Noctilucent clouds—a.k.a. "NLCs"--are a delight for high-latitude sky watchers, and around the Arctic Circle their season of visibility is always eagerly anticipated.

News flash: This year, NLCs are getting an early start. NASA's AIM spacecraft, which is orbiting Earth on a mission to study noctilucent clouds, started seeing them on May 13th.

"The 2013 season is remarkable because it started in the northern hemisphere a week earlier than any other season that AIM has observed," reports Cora Randall of the Laboratory for Atmospheric and Space Physics at the University of Colorado. "This is quite possibly earlier than ever before."

The early start is extra-puzzling because of the solar cycle. Researchers have long known that NLCs tend to peak during solar minimum and bottom-out during solar maximum—a fairly strong anti-correlation. "If anything, we would have expected a later start this year because the solar cycle is near its maximum," Randall says. "So much for expectations."

For sky watchers, this means it's time to pay attention to the sunset sky, where NLCs are most often seen. An early start could herald brighter clouds and wider visibility than ever before.

Noctilucent clouds were first noticed in the mid-19th century after the eruption of super-volcano Krakatoa. Volcanic ash spread through the atmosphere, painting vivid sunsets that mesmerized observers all around the world. That was when the NLCs appeared. At first people thought they must be some side-effect of the volcano, but long after Krakatoa's ash settled the noctilucent clouds remained.

"They've been with us ever since," says Randall. "Not only that, they are spreading."

When AIM was launched in 2007, the underlying cause of NLCs was still unknown. Researchers knew they formed 83 km above Earth's surface where the atmosphere meets the vacuum of space--but that's about all. AIM quickly filled in the gaps.

"It turns out that meteoroids play an important role in the formation of NLCs," explains Hampton University Professor James Russell, the principal investigator of AIM. "Specks of debris from disintegrating meteors act as nucleating points where water molecules can gather and crystallize."

Early NLCs (geometry, med) NLCs appear during summer because that is when water molecules are wafted up from the lower atmosphere to mix with the "meteor smoke." That is also the time when the upper atmosphere is ironically coldest.

Back in the 19th century, NLCs were confined to high latitudes. You had to go to Alaska or Scandinavia to see them. In recent years, however, they have been sighted as far south as Utah, Colorado, and Nebraska. Some researchers believe that the spread of NLCs is a sign of climate change.

One of the greenhouse gases that has become more abundant in Earth's atmosphere since the 19th century is methane. "When methane makes its way into the upper atmosphere, it is oxidized by a complex series of reactions to form water vapor," says Russell. "This extra water vapor is then available to grow ice crystals for NLCs."

The early start of the 2013 season appears to be caused by a change in atmospheric “teleconnections.”

“Half-a-world away from where the northern NLCs are forming, strong winds in the southern stratosphere are altering global circulation patterns,” explains Randall. "This year more water vapor is being pushed into the high atmosphere where NLCs love to form, and the air there is getting colder."

"All of this has come as an interesting surprise for us," notes Russell. "When we launched AIM, our interest was in the clouds themselves. But now NLCs are teaching us about connections between different layers of the atmosphere that operate over great distances. Our ability to study these connections will surely lead to new understanding about how our atmosphere works."
【652words】

发表于 2013-6-10 21:35:38 | 显示全部楼层

沙发沙发 各种开心!!!
==================================
嗯 没礼貌了 忘了谢谢米米姐

Time 1  1'28''
Some combined power of stars pulls the plants close and keep the plants in stable obits.
inward 内部的 向内的 精神的 inbound 入境的 归本国的

Time 2  2'13''
Three theories about HOt Jupiter's travel to the stars. The third one was qualified to be right.

Time 3  1'42''
Further research about the correlation of farther obit distance and the massive stars.

Time 4  2'05''
Research of a recurring nova and its eject condition.
blob 一滴 一抹 v.弄脏 得零分  erupt 爆发 喷出 长牙  siphone off 吸走 vicinity 附近

Time 5  2'22''
Research on light ejected from the nova
vast 广阔的 巨大的 大量的  light echo 回光

Obstacle  感觉读的还挺顺的 就是按错了 把计时给弄没了 555~~
NASA's test test about how much people can accept for noise of
supersonic. This result will help scientists to evaluate the air
transportation in future.

发表于 2013-6-10 21:48:27 | 显示全部楼层
前排~~~~楼主辛苦

_________________________________________
Speed
00:42
01:10
01:49
01:13
00:11
01:14
01:27

Obstacle
02:31
Main idea: Research in NASA
Attitude:   Objective
Structure:
               1) Origin of the test
               2) Structure of the test
               3) Target of the test

发表于 2013-6-10 21:55:47 | 显示全部楼层
谢谢大米!太空知识增长了不少,嘿嘿!
1.1-34
There is new discovery that hot Jupiters, consisting of gas, become stable when the orbit is circular. The discovery is different from that people usually think the planet would become smaller and absorbed by other stars.
2.2-13
The hot Jupiters are similar to the known Jupiter, which is still a gas giant. There are several theories that can explain the movement of the gas around the stars. What's more, scientists find a lot of information to exam these theories.
3.1-38
The tidal theory is tested to explain some situations.
4.2-15
The eruption of Nova surprised a lot of people and spured the interests of scientists. Although the eruption is very furious, the materials is still inside the system.
5.2-52
The author explains the light echo and introduces that scientists detect the movement of the light to make a 3-D map of the structure, thus helping people understand the materials around the Nova rather than the inner materials ejected from the Nova.
6.4-47
This year CNLs are coming eariler than before, a situation that scientists have little knowledge. The siuation is related to the solar cycle. In mid 19 centuries, people began to see the NCLs. In addition, NCLs are thought to can influence the climate. For example, the methan has been increasing since NCLs were discovered. What's more, NCLs can collect more water in the sky and makes it colder. At last, scientists hope that they can know more about NCLs.
发表于 2013-6-10 22:00:06 | 显示全部楼层
大米姐辛苦了~~~
发表于 2013-6-10 22:15:35 | 显示全部楼层
好吧,首页。

Time1 1'15"
Time2 1'44"
Time3 1'12"
Time4 1'34"
Time5 2'00"
Obstacle
A: 3'16"
B: 3'51"

NASA的文,偏难。
发表于 2013-6-10 22:36:50 | 显示全部楼层
Time 8        00:02:09.33        00:13:04.73
Time 7        00:02:38.89        00:10:55.40
Time 6        00:01:26.30        00:08:16.50
Time 5        00:01:56.52        00:06:50.20
Time 4        00:00:58.04        00:04:53.68
Time 3        00:01:36.60        00:03:55.64
Time 2        00:01:23.45        00:02:19.03
Time 1        00:00:55.57        00:00:55.57

第一次参加,碰上一直恐惧的科技类说明文,基本上没看懂多少。。。
发表于 2013-6-10 22:45:54 | 显示全部楼层
留名留名

1'26"
1'45"
1'32"
1'41"
2'16"

3'31"
发表于 2013-6-10 22:46:27 | 显示全部楼层
首页最后一楼!
-------------------------------------------
大米姐,速度似乎比越障难~

1'58''
2'08''
2'04''
16''
2'01''
2'30''

3'38''
4'17''
发表于 2013-6-10 22:51:08 | 显示全部楼层
haobiantai..wodezuowei
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