久久亚洲国产成人影院-久久亚洲国产的中文-久久亚洲国产高清-久久亚洲国产精品-亚洲图片偷拍自拍-亚洲图色视频

  Home>News Center>Life
         
 

NASA: Liquid water once on Mars
(Agencies)
Updated: 2004-03-03 10:19

NASA scientists say the Mars rovers have found what they were looking for -- hard evidence that the red planet was once "soaking wet."


Picture sent back by Opportunity from Mars indicates that the red planet used to be drenched in water.

"We have concluded the rocks here were once soaked in liquid water," said Steve Squyres of Cornell University, the principal investigator for the science instruments on Opportunity and its twin rover, Spirit.

"The second question we've tried to answer: Were these rocks altered by liquid water? We believe definitively, yes," Squyres said.

Squyres and other NASA officials made the announcement at NASA headquarters in Washington after several days of dropping tantalizing hints that something significant had been discovered.


Opportunity used the same tools as used by a field geologist to determine the chemical contents of a rock outcrop near its landing site.
"Three and a half years ago, in July 2000, we were on stage here to talk about sending two rovers to get evidence of past water. NASA and its international partners have turned those dreams to reality," said Ed Weiler, NASA associate administrator for space science.

Scientists used instruments on board the golf cart-sized rovers to study the composition of the rocks and soil on the planet. The rocks' physical appearance, plus the detection of sulfates, make the case for a watery history, and, more importantly, an environment that could have been hospitable to life.

While reporters pushed the scientists to come up with a "when" for the existence of water on Mars, Squyres said it was very difficult to infer an age simply by looking at pictures. He said a physical examination of samples would be the only way to get close to a time frame.

Squyres offered a couple of scenarios on what might have happened that led to the current discoveries:

One is that there was a volcanic eruption -- possibly many eruptions -- and that volcanic ash settled on the Martian surface. Subsequently, water could have percolated through the ground, altering the ash to the chemical composition it has today.

Another possibility, said Squyres, is that there was a salty sea at the Meridiani Planum location, perhaps with currents -- possibly even waves. As the water evaporated, the salt would settle out.

"Both are fundamentally possible," said Squyres. "But we may never know."


The Mars rover Opportunity examines an area dubbed "El Capitan."
Spirit and Opportunity were sent to opposite sides of the planet with the possibility of investigating different types of terrains. Spirit, the first rover to arrive on January 3, landed near the Gusev Crater, which may once have held a lake.

But geologists and other researchers at NASA's Jet Propulsion Laboratory in Pasadena, California, were thrilled when they saw the possibilities surrounding Opportunity, which landed three weeks later. It landed inside a small crater in the Meridiani Planum, one of the flattest surfaces on the planet. And its landing site was within driving distance for the spacecraft to reach an exposed slice of bedrock.

Since its landing January 25, Opportunity has used the same tools as a field geologist to determine the chemical contents of the rocks. Using an alpha particle X-ray spectrometer, a device that can identify chemical elements, scientists have identified a high concentration of sulfur in the bedrock.

The Mars rover Opportunity examines "El Capitan."

Another instrument on board, a Moessbauer spectrometer, has detected an iron sulfate mineral known as jarosite. From their knowledge of rocks on earth, scientists say rocks with as much salt as this Mars rock either formed in water, or had a long exposure to water after they were formed. The scientists say these rocks could have formed in an acidic lake or even hot springs.

Scientists say the case for a watery past is further strengthened by the pictures taken by the rovers' panoramic cameras and its microscopic imager. One target rock named "El Capitan" is filled with random pockmarks. Geologists say a texture like that comes from sites where salt crystals have formed in rocks that have sat in salt water.

Scientists say they have gained other clues from the physical appearance of the rocks. They see a pattern called "crossbedding," which is often the result of wind or water moving across the rock's surface.

So what is ahead for the final few weeks of the rovers' operations on Mars?

"We need to take a close look at the outcropping, and broaden our view to get a better understanding of the geology of the region, which is about the size of Oklahoma," said Joy Crisp, project scientist at the Jet Propulsion Lab. She said there are also plans to drive about 740 meters east to a crater that has been nicknamed "Endurance."

And in the longer term?

"It's clear we have to do a sample return, both for the scientific side and in preparation for human landing," said Weiler. He said future Mars missions would also include miniaturizing equipment and landing equipment that would help prepare for the eventual landings of humans. That might include tests for toxicity in the soil and determining if there are any materials that humans might find useful when they arrive.

The cost of the two rover missions is about $820 million. With solar panels and lithium-ion battery systems aboard, each rover is expected to function and communicate with Earth for about 90 Mars days, known as "sols." That's the equivalent of 92 earth days.

 
  Today's Top News     Top Life News
 

China puzzled over US filing tax complaint at WTO

 

   
 

Chen, Annette Lu slightly wounded in shooting

 

   
 

Specific reform objectives set for banks

 

   
 

Bush urges allies to stick with united mission

 

   
 

Marriage bells toll in cyber churches

 

   
 

Chinese, French women hold dialogue

 

   
  China on show in song and story
   
  Girl, 14, becomes a mother
   
  Dazzling art works catch collectors' eyes
   
  Liver-transplant patient gives birth
   
  China final of Miss Universe to be held in "Spring City"
   
  Computer game cracked down on for discrediting China's image
   
 
  Go to Another Section  
 
 
  Story Tools  
   
  Related Stories  
   
Rover finds Mars was wet enough for life
   
Mars rover Opportunity makes 'significant' finding
   
Spirit rover digs into first rock on Mars
   
Mars under the microscope
   
Mars rover sees possible water evidence
   
Russia space boss slams U.S. Mars plans
   
NASA: Second Mars rover having problems
  Feature  
  HK pop star Edison Chen punched by youngsters  
Advertisement
         
主站蜘蛛池模板: 欧美三级网 | 国产成人久久精品麻豆二区 | 欧美日韩乱国产 | 久久亚洲不卡一区二区 | 91国高清视频| 免费永久国产在线视频 | 国产呦系列免费 | 亚洲欧美一二三区 | 国产一级强片在线观看 | 一区二区三区免费在线观看 | 中文精品99久久国产 | 2020精品极品国产色在线观看 | 国产一国产一级毛片视频在线 | 日日摸日日碰夜夜爽久久 | 日本一区二区三区在线 视频观看免费 | 国产亚洲欧美精品久久久 | 免费一级毛片在线播放 | 久久综合给合久久狠狠狠97色69 | avove在线播放 | 欧美成人免费一区在线播放 | 亚洲第一区视频在线观看 | 91一级片| 看一级特黄a大片国产 | 三级毛片免费 | 中文字幕亚洲综合久久男男 | 亚洲精品成人一区二区www | 日本在线视频免费看 | 看国产一级毛片 | 日本爽快片100色毛片 | 高清国产美女一级a毛片录 高清国产亚洲va精品 | 欧美日韩精品一区二区 | 免费在线观看一区二区 | 亚洲欧美日韩综合在线一区二区三区 | 永久免费毛片在线播放 | 波多野结衣一区二区三区高清在线 | 欧美一区二区三区激情视频 | 碰碰碰精品视频在线观看 | 久久久久久久一线毛片 | 久久国产午夜精品理论片34页 | 欧美成人吃奶高清视频 | 国产激情一级毛片久久久 |