三级aa视频在线观看-三级国产-三级国产精品一区二区-三级国产三级在线-三级国产在线

  Home>News Center
       
 

NASA notes most distant object in solar system
(Agencies)
Updated: 2004-03-16 10:57

Scientists on Monday announced the discovery of a frozen, shiny red world some 8 billion miles from Earth that is the most distant known object in the solar system.

They are calling it a "planetoid," saying it does not meet the definition of a planet.


These three images show the first detection of the faint distant object dubbed Sedna. Arrows indicate location of the planetoid, which was identified by the slight shift in position noted in these three pictures taken at different times on Nov. 14, 2003. Scientists on Monday, March 15, 2004, announced the discovery of Sedna, the frozen, shiny red world some 8 billion miles from Earth that is the most distant known object in the solar system. [AP]

"There's absolutely nothing like it known in the solar system," said Mike Brown, the California Institute of Technology astronomer who led the NASA-funded team that found it last year.

Named Sedna, after the Inuit goddess who created the sea creatures of the Arctic, the planetoid is 800 to 1,100 miles in diameter, or about three-quarters the size of Pluto, and probably half rock, half ice.

It is currently three times farther from Earth than Pluto, the ninth and outermost planet.

Sedna is the largest object found orbiting the sun since the discovery of Pluto in 1930. It trumps in size another icy world, called Quaoar, discovered by the same team in 2002.

Sedna follows a highly elliptical path around the sun, a circuit that takes 10,500 years to complete. It loops out as far as 84 billion miles from the sun. From Sedna's surface, the sun would appear so small that it could be blocked out by the head of a pin.

It is well beyond the Kuiper Belt, a region of ice and rock just beyond the orbit of Neptune.

Brown and his colleagues believe Sedna is the first known member of the long-hypothesized Oort Cloud, a sphere of material orbiting the sun that explains certain comets. If Sedna is part of the Oort Cloud, the cloud extends much closer inward toward the sun than previously believed.


An artist's rendering shows the recently discovered planetoid Sedna in relation to other bodies in the solar system, including Earth and its Moon; Pluto; and Quaoar, a planetoid beyond Pluto that was until now the largest known object beyond Pluto. [AP Photo]

The Oort theory holds that comets in the cloud probably started out as icy objects in places like the Kuiper Belt that were flung out of the solar system by one of the giant planets.

The location of Sedna suggests that it got stuck where it is because its orbit was affected long ago by a star that is no longer nearby.

"What we think must have happened is that early in the history of the solar system, there must have been many, more stars very close to the sun than there are now," Brown said. The sun, in other words, was born in a tight cluster of many stars.

Sedna is one of the most pristine objects in the solar system.

"Very little has happened to this object since the beginning of the solar system," Brown said. "There's not much else out there, so it hasn't been impacted by other objects, it hasn't been heated by the sun. It really has just been sitting out there at 400 degrees below zero for the past 4.5 billion years."

Brown would not classify Sedna as a planet, based on a definition of a planet as an object considerably more massive than any other object in a similar location.

"Sedna sits all by itself in the very outer reaches of the solar system, but our prediction is there will be many, many more of these objects found over the next five years or over the next decade, and it will turn out that Sedna, in fact, is not the most massive object in its orbit out there," Brown said.

Brown, Chad Trujillo of the Gemini Observatory in Hawaii, and David Rabinowitz of Yale University discovered Sedna last November, using a 48-inch telescope at Caltech's Palomar Observatory east of San Diego.

Within days, other astronomers around the world trained their telescopes, including the recently launched Spitzer Space Telescope, on the object.

"It took us a few weeks of continuing to see this object until we were really convinced we had stumbled on something big," Brown said.

The team also have indirect evidence a tiny moon may trail Sedna, which is redder than all other known solar system bodies except Mars.

 
  Today's Top News     Top China News
 

Office: Beijing watches Taiwan developments closely

 

   
 

State tightens farmland protection

 

   
 

Doctor starts 49-day fast to test TCM regimen

 

   
 

Fighting follows Afghan minister's killing

 

   
 

China values military ties with neighbors

 

   
 

Dads ask: 'Is this my child?'

 

   
  Three Gorges Dam Project sparks new relocation
   
  Long March III A chosen for lunar mission
   
  Education key to ending sex trade
   
  China values military ties with neighbors
   
  Going-west still a top development strategy
   
  Office: Beijing watches Taiwan developments closely
   
 
  Go to Another Section  
 
 
  Story Tools  
   
  News Talk  
  Are the Chen-Lu shootings a fabricated hoax or an amateurish bungling  
Advertisement
         
主站蜘蛛池模板: 婷婷综合 在线 | a4yy欧美一区二区三区 | jizjizjiz亚洲大全 | 国产精品 主播精选 网红 | 黄色地址 | 欧美日韩一区二区三区免费 | 青青草伊人网 | 亚洲国产aaa毛片无费看 | 色网综合| 精品一区二区三区视频在线观看免 | 求黄色网 | 国产成人精品777 | 亚洲美女色在线欧洲美女 | 成人日韩视频 | 欧美一级大黄 | www亚洲 | 国产网曝手机视频在线观看 | 亚洲精品系列 | 1024国产基地| 特级aa毛片在线播放 | 婷婷国产在线 | 澳门一级毛片免费播放 | 国产v在线在线观看羞羞答答 | 日韩视频在线观看一区二区 | 一区二区三区国模大胆 | 亚洲最大在线视频 | 2021久久精品国产99国产 | 色综合色狠狠天天久久婷婷基地 | 国外免费一级 | 狠狠色婷婷 | 日韩在线毛片 | 伊人久久中文字幕 | 国产播放啪视频免费视频 | 九一精品视频 | 任我爽在线视频精品凹凸精品分类 | 欧美日韩国产一区二区三区播放 | 国产乱码精品一区二区三区网页版 | 色黄网站aaaaaa级毛片 | 久草在线播放视频 | 久久精品免观看国产成人 | 日韩精品一级a毛片 |