首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
NASA’s new Mars probe, a $ 2. 5 billion, nuclear-powered rover the size of a small car, is at the Florida launch site being prep
NASA’s new Mars probe, a $ 2. 5 billion, nuclear-powered rover the size of a small car, is at the Florida launch site being prep
admin
2019-06-10
28
问题
NASA’s new Mars probe, a $ 2. 5 billion, nuclear-powered rover the size of a small car, is at the Florida launch site being prepared for its nine-month journey to the red planet, with one key issue still unresolved — where to land.
The Mars Science Laboratory, nicknamed Curiosity, will delve deeper than any previous science mission to answer the age-old question about whether there is life beyond Earth. The goal of the project is to determine if the region where Curiosity lands has or ever had the right conditions to support microbial life.
Scientists spent years poring over pictures and analyzing chemical data collected by a fleet of robotic spacecraft circling Mars before narrowing down the options to four finalists; Eberswalde Crater, Mawrth Vallis, Holden Crater and Gale Crater.
" Each site has things that make it good and things that make it not quite so good," said planetary scientist Matt Golombek. " It’s kind of hard to select because it boils down to which kind of science is important to you, and that’s almost personal.
The rover will touch down within a 12. 4-by-15. 5 mile targeted area, a relatively small patch of real estate for interplanetary travel. Being able to make a precision touchdown hasn’t made things easy for scientists tapped to choose Curiosity’s landing spot. In the past, lots of scientifically interesting sites were eliminated because of concerns the spacecraft wouldn’t be able to make a safe landing.
Eberswalde Crater stands out among the four contenders because of a single, stunning geologic feature -— a delta, believed to be a buildup of sediment left by flowing water.
" If you want a site that probably has the highest chance of preserving organics and biosignatures that might have existed, this is the place," Golombek said. " It’s just a spectacular example where water came and built up a sediment. "
The attractive Eberswalde site, however, has a serious drawback as well. If its deposits turn out to be nothing more than clay-dusted rocks, the mission would be largely a bust.
The next candidate site, Mawrth Vallis, is an open book of Martian history, with exposed valley walls that date back about 3.7 billion years, nearly as old as the planet itself. Its clays, known as phyllosilicates, form in the presence of water, believed to be a necessary ingredient for life. Mawrth’s short-coming is that scientists don’t understand how it formed. Water that once flowed in the valley could have been far too acidic for life to flourish.
The primary purpose of the passage is to discuss______.
选项
A、the controversy over the mission carried out by Curiosity
B、the age-old efforts to search for life beyond the earth
C、the power of the nuclear-driven probe in collecting data
D、the best place for the landing of a new Mars probe
答案
D
解析
本题是推理题,考查第一段最后一行中“…with one key issue still unresolved”的意思。
转载请注明原文地址:https://kaotiyun.com/show/EqUO777K
0
考博英语
相关试题推荐
Inresponse,peasantsupanddowntheAmazon,hereinBrazilandinneighboringcountrieslikePeru,areformingcooperativesto
Easternmedicinesarebecomingmorepopularinthewest,butfewpeoplerealizehowlongthetwocultureshaveexchangedideas.
Freedomofexpressionisnotnecessarilya______force:communitiesthatencourageitoftenfeellessthreatenedbysocialunrest
Cellscannotremainaliveoutsidecertainlimitsoftemperature,andmuchnarrowerlimitsmarkthebound-ariesofeffectivefunc
TheEconomistIntelligenceUnit(EIU)earnestlyattemptstomeasurewhichcountrywillprovidethebestopportunitiesforahealth
Lawsofcompulsiveschoolingfunnelchildrenintoschoolataprescribedageirrespectiveofwhethertheyareready.Manypa
Thousandsofpeople______fromGreeceeveryyeartoworkinWestGermany.
Somesocialcriticstookadimviewoftheindustrialismofthenineteenthcentury,believingthatit______aharsh,crudelife-s
【T1】Becauseanalysisultimatelyrestswiththethinkingandchoicesoftheresearcher,qualitativestudiesingeneralarelimite
Theywereforcedto______onnecessitiesinordertomaketheirlimitedsupplieslastthelongishwinter.
随机试题
美国管理学家彼得.德鲁克认为,管理者的第一个责任是()
低铜饮食适用于()。
关于因果关系,下列哪些选项是错误的?(2008—卷二—52,多)
项目决策分析与评价一般分为三个阶段,下面不属于其阶段内容的是()。
采购部应立足于生产要求编制预算,而生产预算应当基于销售预期,说明预算的目的是()。
下列各项中,按照有关规定可以免征个人所得税的有()。
音乐教育搭载移动互联网技术。正在实现音乐培训线上与线下资源的整合。互联网为音乐教育提供了新形式,在通过线上服务提供音乐教育的交流平台,整合垂直领域学习资源等方面________。然而,目前真正能够满足音乐学习者所需的音乐教育平台却________。填入画横
盲人的听觉、触觉非常灵敏,说明人的身心发展具有()。
未来政府财政预算改革的基本取向是建立公共财政,预算资金安排要体现公共性、政策性的客观要求。由手节能具有鲜明的公益性特征,属于社会共同需要的范畴,因此,公共预算设立节能项目与公共预算的改革方向是吻合的。在我国财政经济实力不断增强的背景下,加之必要的预算结构调
大学刚毕业那会儿,我被分配到一个偏远的林区小镇当教师,工资低得可怜。其实我有着不少优势呢,教学基本功不错,还擅长写作。于是,我一边抱怨命运不公,一边羡慕那些拥有一份体面的工作、一份优厚薪水的同窗。这样一来,不仅对工作没了热情,而且连写作也没兴趣。我整天琢磨
最新回复
(
0
)