www射-国产免费一级-欧美福利-亚洲成人福利-成人一区在线观看-亚州成人

您現(xiàn)在的位置: Language Tips> Audio & Video> Normal Speed News  
   
 





 
US space agency plans solar probe
[ 2008-06-13 09:43 ]

Download

The U.S. space agency is planning to send a probe to the sun to gather data and shed light on basic questions about how the star operates and its effects on Earth. VOA's Michael Bowman reports from Washington, the initiative entails numerous technological challenges that will test the skill and ingenuity of engineers assigned to the project.

It is the brightest, most prominent feature of our sky, yet in many ways the sun is shrouded in mystery.

"We have never had a voyage to a star. We do not know what it does up close, next to its visible surface. And we do not know the [sun's] physical processes very well," said Richard Fisher, who heads NASA's Heliophysics Division, the body responsible for studying the sun.

Among the questions that have long-stumped researchers: how can it be that the sun's outer atmosphere, the corona, is hundreds of times hotter than the star's surface? What force is responsible for solar winds - the stream of charged particles contributing to geo-magnetic storms that affect electrical and communications systems on earth - given that no organized wind has been detected at the sun's surface?

To get some answers, NASA hopes to launch a probe weighing about half a ton into the sun's atmosphere to measure the magnetic field, sense plasma waves, and analyze particles emitted from the star. A telescopic imager will take three-dimensional pictures of the corona.

"We are going to go close to a star. It is going to be very hot. There is a technological issue of how you generate power; there is a lot of sunlight, but you cannot use all of it. There is a technical problem of how you shield the payload from all the radiance. And then you have to transmit data halfway across the solar system, almost," Fisher said.

Planners envision a carbon-composite heat shield that will have to withstand temperatures in excess of 1,400 degrees Celsius and survive massive radiation blasts. As one might expect, the craft will be solar-powered with retractable liquid-cooled solar panels.

NASA chose the Johns Hopkins University's Applied Physics Lab to design and build the probe.

Project Manager Andrew Dantzler says he relishes the unprecedented engineering challenges facing his team.

"It really is a convolution of technologies that have advanced over the last several years: high-temperature materials, more-efficient solar arrays. It is technology like that that have made this [project] possible," he said.

Dantzler says, when the probe is launched, perhaps as early as 2015, it will constitute the fulfillment of a goal that astronomers and other scientists set forth decades ago.

"This idea goes all the way back to the beginning of the space age. In 1958, the National Research Council first introduced the concept of sending a probe close to the sun. But it is only recently that we have come up with the optimal way of doing that kind of mission."

NASA says, for now, the solar probe mission is an entirely U.S. endeavor, but that space agencies of other nations have expressed an interest in the project and that collaboration would be welcomed.

NASA says, not only will the probe generate information that could prove valuable in predicting solar storms that interrupt electrical systems on Earth, the craft could potentially serve as an early-warning system for solar activity that might affect future human space travel.

payload:the total weight of passengers and cargo that an aircraft carries or can carry(有效負(fù)荷)

(Source: VOA 英語點(diǎn)津姍姍編輯)

 
英語點(diǎn)津版權(quán)說明:凡注明來源為“英語點(diǎn)津:XXX(署名)”的原創(chuàng)作品,除與中國(guó)日?qǐng)?bào)網(wǎng)簽署英語點(diǎn)津內(nèi)容授權(quán)協(xié)議的網(wǎng)站外,其他任何網(wǎng)站或單位未經(jīng)允許不得非法盜鏈、轉(zhuǎn)載和使用,違者必究。如需使用,請(qǐng)與010-84883631聯(lián)系;凡本網(wǎng)注明“來源:XXX(非英語點(diǎn)津)”的作品,均轉(zhuǎn)載自其它媒體,目的在于傳播更多信息,其他媒體如需轉(zhuǎn)載,請(qǐng)與稿件來源方聯(lián)系,如產(chǎn)生任何問題與本網(wǎng)無關(guān);本網(wǎng)所發(fā)布的歌曲、電影片段,版權(quán)歸原作者所有,僅供學(xué)習(xí)與研究,如果侵權(quán),請(qǐng)?zhí)峁┌鏅?quán)證明,以便盡快刪除。
相關(guān)文章 Related Story
 
 
 
本頻道最新推薦
 
Walking in the US first lady's shoes
“準(zhǔn)確無誤”如何表達(dá)
英國(guó)新晉超女蘇珊大媽改頭換面
豬流感 swine flu
你有l(wèi)ottery mentality嗎
翻吧推薦
 
論壇熱貼
 
別亂扔垃圾。怎么譯這個(gè)亂字呀?
橘子,橙子用英文怎么區(qū)分?
看Gossip Girl學(xué)英語
端午節(jié)怎么翻譯?
母親,您在天堂還好嗎?

 

主站蜘蛛池模板: 久久免费视频在线观看30 | 99国产精品视频免费观看 | 特级aaa片毛片免费观看 | 国产福利一区二区三区 | 久久亚洲精品国产精品777777 | 国产精品久久久久久久久免费 | 久久中文字幕免费视频 | 成人免费福利片在线观看 | 久久久一本精品99久久精品66 | 成人久久18免费软件 | 国产一区亚洲二区三区 | 草草国产成人免费视频 | 91大神大战丝袜美女在线观看 | 欧美精品另类hdvideo | 久夜色精品国产一区二区三区 | 国产aⅴ一区二区三区 | 色综合天天综合网看在线影院 | 点击进入不卡毛片免费观看 | 经典三级在线视频 | 最新国产三级在线不卡视频 | 亚洲国产精品久久人人爱 | 永久精品免费影院在线观看网站 | 国产精品亚洲欧美 | 久久久久久国产精品免费免 | 成熟女人免费一级毛片 | 国产在线精品福利一区二区三区 | 欧美一级大尺度毛片 | 国内一级特黄女人精品片 | 99久久精品一区二区三区 | 精品国产91久久久久久久 | 性感毛片 | 农村寡妇野外情一级毛片 | 亚洲国产第一区二区三区 | 成人在线免费观看视频 | 欧美成人片在线 | 午夜三级网 | 免费一级成人免费观看 | 午夜在线播放免费人成无 | 国产高清美女一级a毛片久久w | 性欧美高清久久久久久久 | 亚洲综合久久1区2区3区 |