Mars Rover Finds Evidence of Ancient Sea

Mars Rover Finds Evidence of Ancient Sea

 

David McAlary

 

The U.S. space agency NASA says Mars once had a shallow, salty sea that could have supported life. The evidence has come from chemical and physical traits of rocks being explored by one of the two robotic rovers on the red planet.

 

Mission scientists say instruments on the rover Opportunity have sensed sure signs in martian rocks that the planet had at least briny¹ pools of water and likely a more extensive salt water ocean.

 

"We believe that Opportunity is parked on what once was the shoreline of a salty sea." This is Cornell University geologist² Steven Squyres, who says the element bromium, a component³ of salt, is one clue in the rocks. Bromium is found in rocks formed in sea water on Earth. Another clue is that the layers of the martian rock are wavy⁴, not flat and parallel to each other. This indicates that the sediments⁶ of material that formed them were washed along and deposited by ripples⁷ of water. "This was a shallow sea. These are salt flats. These are the kinds of environments that are very suitable for life. Now we don't know that life was there, but we have an environment that would have been suitable for life."

 

When the scientists presented the first firm evidence of water on Mars three weeks ago, they could say only that the rock Opportunity explored was altered by water. But they left open the possibility that the rock was not formed by water in the first place. Now they are saying that the rock did form in water at least five centimeters deep and possibly deeper.

 

Photographs of the internal rock structure show that some layers lie at angles to the main layers. The scientists say that if the sediments had dropped into place after a volcano, for example, they would have fallen evenly, creating parallel layers.

 

A sediment⁵ expert at the U.S. Geological Survey who was not involved in the research, David Rubin, says pictures of the rock layers he has seen do not indicate that wind had deposited the sediments. "I was astonished. There on Mars were sedimentary structures just like we see on Earth. You can go out to your nearest beach or creek⁸ and take a shovel⁹ and dig in and see some of these same kinds of structures."

 

Still unanswered, however, are how deep the Martian water was, how much area it covered, and how long it stood on what has since become a dry, barren planet. Next year, NASA plans to launch a satellite to orbit Mars with instruments to help answer the question of how extensive the salt water ocean might have been.

 

NASA's chief of space science, Ed Weiler, said the new findings from Opportunity will influence where to send another U.S. rover mission later in the decade to retrieve¹⁰ soil and rock samples for return to Earth so scientists can probe them for microbial life. "If you have an interest in searching for fossils on Mars, this is the first place you want to go."

 

注释：

NASA [5nAsE] abbr. National Aeronautics¹¹ and Space Administration（美国）国家航空和宇宙航行局

robotic [rEu5bCtik] adj. 机器人的

rover [5rEuvE] n. 飞行器

martian [5mB:FiEn] adj. 火星的

briny [5braini] adj. 盐水的，咸的

shoreline [5FC:lain] n. 海岸线

Cornell University 康奈尔大学，位于美国纽约，建于1865年，是由艾兹拉·康乃尔创建的。在所有“常春藤盟校”中，康乃尔是历史最短的一个，而同时它又是最大的一个。

bromium [5brEumaiz] vt. <化>溴化

parallel [5pArElel] adj. 平行的

sediment [5sedimEnt] n. 沉淀物，沉积

centimeter [5sentImi:tE(r)] n. 厘米

deposit [di5pCzit] v. 堆积，沉积

creek [kri:k] n. 小溪，小河

barren [5bArEn] adj. 贫瘠的

orbit [5C:bit] vt. 绕……轨道而行

fossil [5fCsl] n. 化石

1 briny   

adj.盐水的；很咸的；n.海洋

参考例句：

• The briny water is not good for the growth of the trees.海水不利于这种树木的生长。
• The briny air gave a foretaste of the nearby sea.咸空气是快近海的前兆。

2 geologist   

n.地质学家

参考例句：

• The geologist found many uncovered fossils in the valley.在那山谷里，地质学家发现了许多裸露的化石。
• He was a geologist,rated by his cronies as the best in the business.他是一位地质学家，被他的老朋友们看做是这门行当中最好的一位。

3 component   

n.组成部分，成分，元件；adj.组成的，合成的

参考例句：

• Each component is carefully checked before assembly.每个零件在装配前都经过仔细检查。
• Blade and handle are the component parts of a knife.刀身和刀柄是一把刀的组成部分。

4 wavy   

adj.有波浪的，多浪的，波浪状的，波动的，不稳定的

参考例句：

• She drew a wavy line under the word.她在这个词的下面画了一条波纹线。
• His wavy hair was too long and flopped just beneath his brow.他的波浪式头发太长了，正好垂在他的眉毛下。

5 sediment   

n.沉淀，沉渣，沉积(物)

参考例句：

• The sediment settled and the water was clear.杂质沉淀后，水变清了。
• Sediment begins to choke the channel's opening.沉积物开始淤塞河道口。

6 sediments   

沉淀物( sediment的名词复数 )； 沉积物

参考例句：

• When deposited, 70-80% of the volume of muddy sediments may be water. 泥质沉积物沉积后，体积的70-80％是水。
• Oligocene erosion had truncated the sediments draped over the dome. 覆盖于穹丘上的沉积岩为渐新世侵蚀所截削。

7 ripples   

逐渐扩散的感觉( ripple的名词复数 )

参考例句：

• The moon danced on the ripples. 月亮在涟漪上舞动。
• The sea leaves ripples on the sand. 海水在沙滩上留下了波痕。

8 creek   

n.小溪，小河，小湾

参考例句：

• He sprang through the creek.他跳过小河。
• People sunbathe in the nude on the rocks above the creek.人们在露出小溪的岩石上裸体晒日光浴。

9 shovel   

n.铁锨，铲子，一铲之量；v.铲，铲出

参考例句：

• He was working with a pick and shovel.他在用镐和铲干活。
• He seized a shovel and set to.他拿起一把铲就干上了。

10 retrieve   

vt.重新得到，收回；挽回，补救；检索

参考例句：

• He was determined to retrieve his honor.他决心恢复名誉。
• The men were trying to retrieve weapons left when the army abandoned the island.士兵们正试图找回军队从该岛撤退时留下的武器。

11 aeronautics   

n.航空术，航空学

参考例句：

• National Aeronautics and Space undertakings have made great progress.国家的航空航天事业有了很大的发展。
• He devoted every spare moment to aeronautics.他把他所有多余的时间用在航空学上。