首页
登录
职称英语
WATER AND LIFE ON MARS1 The presence or absence of water
WATER AND LIFE ON MARS1 The presence or absence of water
游客
2024-01-04
55
管理
问题
WATER AND LIFE ON MARS
1 The presence or absence of water has a direct bearing on the possibility of life on other planets. In the nineteenth century, it was commonly accepted that life, perhaps even intelligent life, was widespread in the solar system, and Mars was an obvious target in the search for life. New photographic technology offered a way for astronomers to learn more about the red planet. In 1888, Italian astronomer Giovanni Schiaparelli produced images that showed a network of long, thin, dark lines crossing the surface of Mars. He called these features canali in Italian, which became "canals" or "channels" in English. The strange appearance of the canals suggested to some scientists that they had been formed artificially rather than naturally. The mystery deepened when Schiaparelli observed that many of the canals in the photographs were actually double.
2 Other photographic images of Mars revealed its seasonally changing polar ice caps and features that appeared to be ancient islands located in what was now a dry streambed. When the islands were first discovered, some scientists speculated that a thick water-laden atmosphere capable of generating heavy rains had once existed on Mars. However, others remained unconvinced of the presence of water. Then, in 1963, a team of astronomers obtained a good photographic plate of the near-infrared spectrum of Mars. The photograph showed that, faintly but definitely, water vapor lines could be seen. This photograph established that there really was water on Mars, though the amount was very small.
Today, the presence of water vapor in the Martian atmosphere is generally accepted, as is the belief that the atmosphere was once much denser than it is now, with a much greater abundance of water vapor.
3 The surface of Mars is dry today, but it does contain significant amounts of ice and signs that liquid water once flowed over the planet. All of the locations where evidence of water has been found are ancient, probably formed very early in Martian history. Data transmitted from spacecraft on Mars in 2004 have revealed that water was once common across a vast region of the planet, possibly as shallow lakes or seas that dried out and then filled up again. There are signs that the wind blew debris around during dry stages. These seas and lakes extended across hundreds of thousands of square miles, creating
habitable
conditions during long stretches of time billions of years ago.
4 Evidence of water includes the presence of various minerals known as evaporates, deposits left behind when liquid water turns to vapor. Small areas of mineral deposits have been found in Valles Marineris, a huge hole on Mars that is larger than the Grand Canyon on Earth. The minerals there contain water, so they had to be formed in the presence of water. Geologic research has also turned up clay and gypsum deposits that were formed by water in the soil. Rocks that clearly formed in water extend throughout 300 meters of layered materials in several locations across the Martian plains. The layers were built up over time, which means water was present, at least temporarily, for extended periods on ancient Mars.
5 Besides the ice packs at Mars’s poles, astronomers have discovered a frozen sea near its equator. This frozen sea is the size of the North Sea on Earth and appears similar to the ice packs on Antarctica. Scientists have also detected evidence of lava flows 20 million years ago as well as signs that some volcanoes may still be active. Several recently formed volcanic cones near Mars’s North Pole indicate that the planet’s core may interact with the surface, meaning there was both warmth and moisture in the recent pas-circumstances that might have supported life.
6 Liquid water is the key ingredient for life as we know it. Of all the other planets in the solar system, Mars is most like Earth. The fact that water existed on ancient Mars does not necessarily mean life ever emerged there; however, all of the available evidence does suggest that Mars meets all the requirements that are needed for life to exist. [br] The phrase filled up in paragraph 3 is closest in meaning to
选项
A、got smaller
B、were frozen
C、became wet
D、turned to rock
答案
C
解析
Filled up means became wet in this context. Clues: ... water was once common...; ...shallow lakes or seas that dried out and then filled up again. The next sentence mentions dry stages, which implies that there were wet stages and dry stages. (1.4)
转载请注明原文地址:https://tihaiku.com/zcyy/3332642.html
相关试题推荐
Protectivebehaviorsof(amphibians)includehiding(in)thepresenceofdanger
"ExcusedAbsence"Readashortpassageandlistentoatalkonthesamet
WATERANDLIFEONMARS1Thepresenceorabsenceofwater
WATERANDLIFEONMARS1Thepresenceorabsenceofwater
WATERANDLIFEONMARS1Thepresenceorabsenceofwater
WATERANDLIFEONMARS1Thepresenceorabsenceofwater
Oneinterpretationregardingtheabsenceoffossilsduringthisimportant10
IndividualPerformanceandthePresenceofOthersP1:Aperson’sperformanceon
IndividualPerformanceandthePresenceofOthersP1:Aperson’sperformanceon
IndividualPerformanceandthePresenceofOthersP1:Aperson’sperformanceon
随机试题
SelectivecollegesanduniversitiesintheU.S.areunderfireforbeingtoo
PartⅡReadingComprehension(SkimmingandScanning)Directions:Inthispart,y
射线辐照红细胞之后,对有核细胞的杀死率为( )。A.90% B.70% C
孕妇,28岁。妊娠具体月数不详,欲判断胎儿成熟度,行羊膜腔穿刺。羊水卵磷脂/鞘磷
第三产程处理错误的是A、胎盘娩出后详细检查胎盘、胎膜是否完整 B、检查阴道、会
肌丝滑行时,与横桥结合的蛋白是A.肌球蛋白 B.肌动蛋白 C.肌钙蛋白 D
一住店客人未付房钱即想离开旅馆去车站。旅馆服务员揪住他不让走,并打报警电话。客人
(2019年真题)某男,65岁,宿有喘病,气短,动则喘甚,小便清长,腰酸痛,大便
(2018年真题)某女,78岁,患高血压病10年,因感冒发热1天而就诊于中医。刻
汽轮机第一次试启动的条件不包括()。A.汽轮机安装完毕 B.辅机部分试运合格
最新回复
(
0
)