Home>News Center>World
         
 

NASA probe leaves crater, debris trail
(Agencies)
Updated: 2005-07-05 06:29

PASADENA, Calif - A spectacular collision between a spacecraft and a comet has freed a huge plume of primordial material from the comet's nucleus that could unlock the secret of how life arrived on Earth, NASA scientists said on Monday.

A NASA probe collides with comet Tempel 1 in this image taken by the impactor's mother ship, capturing the climax to the Deep Impact mission. [Agencies]
The first images returned from the Deep Impact fly-by spacecraft showed a small fireball followed by a much larger, incandescent flash that engulfed one end of the comet Tempel 1 as the impactor smashed into its surface at 1:52 a.m. EDT (0552 GMT) on Monday.

The impactor was vaporized upon slamming into the comet at 23,000 mph (37,000 kph) -- the speed it would take to fly from New York to Los Angeles in about six minutes.

The collision, which occurred 83 million miles from Earth, marks the first time a spacecraft has come in contact with a comet.

Observatories on the ground reported that the explosion brightened the comet by a factor of 5 within 15 minutes of impact, scientists at NASA's Jet Propulsion Laboratory in Pasadena said.

Scientists could not immediately determine the size of the crater produced by the impact because of the large plume of ice, dust and gases streaming out and obscuring one end of the comet, which is half the size of Manhattan.

"We are waiting for the outgassing to stop. It's clear it's was still coming out for several hours ... and could go on for weeks," principal scientist Mike A'Hearn told reporters at a Monday news conference.

The Deep Impact team had estimated the washing machine-sized impactor would punch a hole anywhere from the size of a house to a football stadium, depending on the composition of the comet's surface.

"We know that we created quite a crater. We believe it penetrated quite deeply so we know we'll get a good look at the interior," Project Manager Rick Grammier said on Monday. "We just have a wealth of scientific information to go through in the next few months."

'BIG CHANGES'

The impact sent up twin plumes of debris, the first appearing as a narrow column that cast a long shadow across the comet. Another plume appeared seconds later on the heels of a brighter explosion, then fanned out in a star shape. Scientists said the plumes stretched for "at least thousands of kilometers" into space.

Co-investigator Pete Schultz said the twin flashes showed that the impactor encountered softer, layered material on the comet's surface then hit a thick, hard crust.

A spectrometer aboard the fly-by spacecraft captured "big changes" in the spectra of debris flying up from the crater, indicating a variety of materials were freed by the impact, A'Hearn said.

Comets are made of gas, dust, organic material and ice from the solar system's farthest regions. Because they were not heated by the Sun during the formation of the solar system, comets retain the original chemical mixture from which the planets formed 4.6 billion years ago.

Scientists think comets may be responsible for first bringing water and organic material to Earth by crashing into its surface during a period of heavy comet activity 3.9 billion years ago -- around the same time as the first signs of life.

Tempel 1's rough surface, closely revealed for the first time in images snapped by the impactor up to 3 seconds before impact, differed markedly from the two other comets scientists have been able to observe up close, A'Hearn said.

The surface showed what appeared to be layering, craters, small bright features and smooth areas that defy physics by stretching around two sides of the comet, he said.

"There is something more going on here than we understand," he said.

A'Hearn also said the Deep Impact team has been forced to reevaluate its ideas about Tempel 1's shape, which is more like a muffin or a loaf of bread than a pickle.

The $333-million Deep Impact mission is the eighth in NASA's Discovery Program to produce relatively cheap missions, such as the 1997 Mars Pathfinder, to explore the solar system.



Space shuttle Discovery launch delayed
Blair plans measures to uproot extremism
Pakistan train crash carnage kills 128
 
  Today's Top News     Top World News
 

Taiwan's KMT Party to elect new leader Saturday

 

   
 

'No trouble brewing,' beer industry insists

 

   
 

Critics see security threat in Unocal bid

 

   
 

DPRK: Nuke-free peninsula our goal

 

   
 

Workplace death toll set to soar in China

 

   
 

No foreign controlling stakes in steel firms

 

   
  Judge: Saddam trial could begin next month
   
  DPRK: Nuke-free peninsula our goal
   
  Pakistan train crash carnage kills 128
   
  NASA delays shuttle launch till Saturday
   
  Annan advocates UN Council expansion now
   
  Israel seals off Gaza Strip settlements
   
 
  Go to Another Section  
 
 
  Story Tools  
   
  Related Stories  
   
Russian astrologist sues NASA over comet crash
   
Russian astrologist sues NASA over comet crash
   
NASA space probe hits comet target
   
Comet probe ready for 'suicidal' crash
   
NASA launches comet-smashing spacecraft
   
Comet collision may tell of solar origin
   
NASA Deep Impact comet probe set to launch
  News Talk  
  Are the Republicans exploiting the memory of 9/11?  
Advertisement
         
主站蜘蛛池模板: 97人伦影院a级毛片| 国产ts在线播放| 久久久久久a亚洲欧洲AV| 欧美日韩一区二区三区免费不卡| 国产在视频线精品视频| 2019天堂精品视频在线观看| 日本18xxx| 亚洲va久久久噜噜噜久久天堂| 精品无码国产一区二区三区51安 | 国产真实乱16部种子| 97成人碰碰久久人人超级碰OO| 女生张开腿给男生捅| 久久精品成人国产午夜| 真正全免费视频a毛片| 国产AV一区二区精品凹凸| 3344免费播放观看视频| 天天天天做夜夜夜做| 一级毛片免费不卡| 最近在线中文字幕影院网| 免费人成视频x8x8入口| 成年美女黄网站色| 国产精品国产三级国产普通话| 97精品在线播放| 大陆一级毛片免费视频观看i| 一区二区三区国产最好的精华液 | 欧美性大战XXXXX久久久√| 亚洲精品91在线| 老司机永久免费网站在线观看| 精产国品一二三产区M553| 天堂а√在线官网| 一本加勒比HEZYO无码人妻| 成人看免费一级毛片| 丰满熟妇乱又伦| 欧美日韩亚洲国产精品| 亚洲香蕉免费有线视频| 苏玥马强百文择| 国产精品无码久久综合| 99久久精品免费看国产 | 无码人妻丰满熟妇区五十路 | 国产亚洲欧美视频| 538在线播放|