2018年 3月亞太區SAT考試回顧

2018年3月SAT亞太區首考結束,菁英教研團隊第一時間全方位回顧考情,為亞太地區最詳細、最準確、最權威,希望對本次考試的考生,以及準備參加今年5月亞太和8月北美的考生有所幫助。

SAT考試【總體觀察】

  • 閱讀本次篇章難度水準趨於正常,順序類似於2017年8月北美出題,循證題、詞彙題、圖表題依舊主導學生作答水準。
  • 文法難度居中,考點符合常規,後兩篇語義題居多,語篇題難度較上次12月亞洲較為容易。
  • 數學考試難度偏低,相較12月考試更強調對函數的透徹理解,以及用數學知識解決實際問題的能力。
  • 作文難度居中偏簡單
下載2018年3月SAT考試回顧


Section 1閱讀測驗

【第一篇】

文章概述

作者Ayana Mathis,原文出自於The Twelve Tribes of Hattie. This passage is set in 1923.

文章主要內容

主人公Hattie到達費城火車站的所見所聞以及對該城市看法的轉變;
第一段:Hattie和她的Mother及Sisters坐了三十二小時的火車到達費城,費城火車站人山人海,Hattie被擠出車站,Sisters和Mother並沒有跟上來;
第二段:Hattie在火車站外看到費城街上景象,感慨自己可以在這座城市待下來,但內心仍然緊張不安;Hattie在人群中找Mother和Sisters,但是沒有找到;
第三段:Hattie看到一個黑人婦女向一個白人花商買花;
第四段:黑人婦女不小心把花瓶打碎了,花摔在地上,Hattie認為一場衝突在即,街上的黑人應該都不會捲入這場衝突,但黑人婦女重新給了錢,買了花,這場衝突和平解決;
第五段:Hattie看著街上黑人們的一舉一動,內心改變了對這座城市的看法,決心留在這裡;

題目回顧
  • 主旨題:Which choice can best summarize the passage?
  • 目的題:考察文章第一段片語“round as a marble in her mouth”和“a needle in her chest”的效果和目的;
  • 細節題:Hattie在車站和Mother及Sisters分開,對她造成了什麼影響;
  • 詞彙題:原文詞彙是gained,選項詞彙有reached, increased;
  • Hattie第一次來到費城,她對費城的生活的態度是什麼樣的;
  • 上一題詢證;
  • 黑人婦女和白人花商之間的衝突在即,Hattie認為many black people對此會是什麼反應;
  • 上一題詢證;
  • 目的題:文章最後一段第一句Hattie looks more closely at the crowds on the street的作用;
  • 文章最後一段,文章將費城街上的四個談笑的black girls和佐治亞街上的white girls做了怎樣的對比
文章原文

THIRTY-TWO HOURS AFTER Hattie and her mother and sisters crept through the Georgia woods to the train station, thirty-two hours on hard seats in the commotion of the Negro car, Hattie was startled from a light sleep by the train conductor’s bellow, “Broad Street Station, Philadelphia!” Hattie clambered from the train, her skirt still hemmed with Georgia mud, the dream of Philadelphia round as a marble in her mouth and the fear of it a needle in her chest.


Hattie and Mama, Pearl and Marion climbed the steps from the train platform up into the main hall of the station. It was dim despite the midday sun. The domed roof arched. Pigeons cooed in the rafters. Hattie was only fourteen then, slim as a finger. She stood with her mother and sisters at the crowd’s edge, the four of them waiting for a break in the flow of people so they too might move toward the double doors at the far end of the station. Hattie stepped into the multitude. Mama called, “Come back! You’ll be lost in all those people. You’ll be lost!” Hattie looked back in panic; she thought her mother was right behind her. The crowd was too thick for her to turn back, and she was borne along on the current of people. She gained the double doors and was pushed out onto a long sidewalk that ran the length of the station.


The main thoroughfare was congested with more people than Hattie had ever seen in one place. The sun was high. Automobile exhaust hung in the air alongside the tar smell of asphalt softening in the heat and the sickening odor of garbage rotting. Wheels rumbled on the paving stones, engines revved, paperboys called the headlines. Across the street a man in dirty clothes stood on the corner wailing a song, his hands at his sides, palms upturned. Hattie resisted the urge to cover her ears to block the rushing city sounds. She smelled the absence of trees before she saw it. Things were bigger in Philadelphia—that was true—and there was more of everything, too much of everything. But Hattie did not see a promised land in this tumult. It was, she thought, only Atlanta on a larger scale. She could manage it. But even as she declared herself adequate to the city, her knees knocked under her skirt and sweat rolled down her back. A hundred people had passed her in the few moments she’d been standing outside, but none of them were her mother and sisters. Hattie’s eyes hurt with the effort of scanning the faces of the passersby.


A cart at the end of the sidewalk caught her eye. Hattie had never seen a flower vendor’s cart. A white man sat on a stool with his shirtsleeves rolled and his hat tipped forward against the sun. Hattie set her satchel on the sidewalk and wiped her sweaty palms on her skirt. A Negro woman approached the cart. She indicated a bunch of flowers. The white man stood—he did not hesitate, his body didn’t contort into a posture of menace—and took the flowers from a bucket. Before wrapping them in paper, he shook the water gently from the stems. The Negro woman handed him the money. Had their hands brushed?


As the woman with the flowers took her change and moved to put it in her purse, she upset three of the flower arrangements. Vases and blossom stumbled from the cart and crashed on to the pavement. Hattie stiffened waiting for the inevitable explosion. She waited for the other Negroes to step back and away from the object of the violence that was surely coming. She waited for the moment in which she would have to shield her eyes from the woman and whatever horror would ensue. The vendor stooped to pick up the mess. The Negro woman gesture apologetically and reached into her purse again, presumably to pay for what she’d damaged. Ina couple of minutes it was all settled, and the woman walked on down the street with her nose in the paper cone of flowers, as if nothing had happened.


Hattie looked more closely at the crowd on the sidewalk. The Negroes did not step into the gutters to let the whites pass and they did not stare doggedly at their own feet. Four Negro girls walked by, teenagers like Hattie, chatting to one another. Just girls in conversation, giggling and easy, the way only white girls walked and talked in the city streets of Georgia. Hattie leaned forward to watch them progress down the block. At last, her mother and sisters exited the station and came to stand next to her. “Mama,” Hattie said. “I’ll never go back. Never.”

【第二篇】

文章概述

此題為雙篇文章對比

文章大意

Passage 1:主要採取先抑後揚的手段
第一段:講印度的政府職責缺失,之前外來的統治不適合印度的風土人情,印度人民被課以重稅。
第二段:話風一轉,說其實印度未來還是有希望;
第三段:繼續講之前印度人民被侵略被統治,但是英國幫助其逃脫;
第四段:講現在的政府雖然有犯一些錯,但是還是為人民著想;
Passage 2:主要採取先抑後揚的手段
第一段文章直接說 British ruined our country,認為英國只是利用來華麗的外衣來包裝其私慾,採用愚民手段來麻痹印度人民。作者呼籲:應該認清事實,權利應該掌握在自己的手上。

題目回顧
  • 問的是P1文章的main focus 是如何轉移的。需要通讀全文才能解題,但是題目難度不大:只要抓住段落大意和文章的邏輯就能解題。文章採先抑後揚,先說印度政治狀況混亂,後提到政府其實取得了較好成果。
  • 問原文何處支撐了“British unified India” 難度不大,只要將四個選項帶入。就會發現原文有一句:(i see…dependent states)
  • 詞彙題:attend 和哪個詞意思接近:frequented / maintain/replaced/accompanied
  • 詞彙題:charge 和哪個詞意思接近:care/invasion/accusation/expense
  • 問第二篇的段落大意:文章主旨體現非常清晰鮮明:the British ruined our country
  • 問印度人民對英國統治最初的態度:原文第二篇第3-5句話直接提現:supried ,即一開始認為英國是for their good,為他們著想。
  • 問英國是用何種方式來鞏固它們在印度的統治?答案在文章第二段:通過愚民手段fooled ignorance,blindness
  • 詞彙題:business 和以下哪個詞意思接近:objectives/likehood/movement
  • 問P2作者會如何看待P1作者所說的英國幫助實現印度國內的穩定性:P2作者立場鮮明,反對P1作者,認為只有權利在本國人手中才能實現穩定。
  • 問P2作者如何看P1作者所說的“some plan” 難度不大:作者立場很容易看出,reject 作者在第二段認為英國是利用華麗的外衣來實現一國私慾。
  • 上題循證題
Passage 1原文:

It is true, then, that there was too much foundation for the representations of those satirists and dramatists who held up the character of the English Nabob to the derision and hatred of a former generation. It is true that some disgraceful intrigues, some unjust and cruel wars, some instances of odious perfidy and avarice, stain the annals of our Eastern Empire. It is true that the duties of government and legislation were long wholly neglected or carelessly performed. It is true that when the conquerors at length began to apply themselves in earnest to the discharge of their high functions, they committed the errors natural to rulers who were but imperfectly acquainted with the language and manners of their subjects. It is true that some plans, which were dictated by the purest and most benevolent feelings, have not been attended by the desired success. It is true that India suffers to this day from a heavy burden of taxation and from a defective system of law. It is true, I fear, that in those states which are connected with us by subsidiary alliance, all the evils of oriental despotism have too frequently shown themselves in their most loathsome and destructive form.


[But nowadays its affairs are much improved, and still improving]
[7a] All this is true. Yet in the history and in the present state of our Indian Empire I see ample reason for exultation and for a good hope.


[7b] I see that we have established order where we found confusion. I see that the petty dynasties which were generated by the corruption of the great Mahometan Empire, and which, a century ago, kept all India in constant agitation, have been quelled by one overwhelming power. I see that the predatory tribes, which, in the middle of the last century, passed annually over the harvests of India with the destructive rapidity of a hurricane, have quailed before the velour of a braver and sterner race, have been vanquished, scattered, hunted to their strongholds, and either extirpated by the English sword, or compelled to exchange the pursuits of rapine for those of industry.


[7c] I look back for many years; and I see scarcely a trace of the vices which blemished the splendid fame of the first conquerors of Bengal. I see peace studiously preserved. I see faith inviolably maintained towards feeble and dependent states. I see confidence gradually infused into the minds of suspicious neighbors. I see the horrors of war mitigated by the chivalrous and Christian spirit of Europe. I see examples of moderation and clemency, such as I should seek in vain in the annals of any other victorious and dominant nation. I see captive tyrants, whose treachery and cruelty might have excused a severe retribution, living in security, comfort, and dignity, under the protection of the government which they labored to destroy.


[7d] I see a large body of civil and military functionaries resembling in nothing but capacity and velour those adventurers who, seventy years ago, came hither, laden with wealth and infamy, to parade before our fathers the plundered treasures of Bengal and Tanjore. I reflect with pride that to the doubtful splendor which surrounds the memory of Hastings and of Clive, we can oppose the spotless glory of Elphinstone and Munro. I contemplate with reverence and delight the honorable poverty which is the evidence of rectitude firmly maintained amidst strong temptations. I rejoice to see my countrymen, after ruling millions of subjects, after commanding victorious armies, after dictating terms of peace at the gates of hostile capitals, after administering the revenues of great provinces, after judging the causes of wealthy Zemindars, after residing at the courts of tributary Kings, return to their native land with no more than a decent competence.


Passage 2原文:

From Tilak’s speech on “the tenets of the New Party” (1907) by Bal Gangadhar Tilak, Indian political leader.


Introduction: Bal Gangadhar Tilak (1849-1920) was a major political leader of Maharashtra. He sided with the „Extremists“ and broke with the „Moderates“when the Indian National Congress split in December 1907. Shortly after the Calcutta Congress of December 1906 when the split was narrowly avoided he spoke in Calcutta on January 2,1907 outlining the tenets of the "Extremists" In 1908 he was sentenced to six years imprisonment for „sedition“. After his release in 1914 he became a leader of the „Home Rule League“. His famous slogan „Swaraj (Home Rule) is my birthright – and I will have it“was often quoted by Indian nationalists.
(see also AHOI, Ch. 7, section: The partition of Bengal and the rise of extremism)


Pax Britannica has been established in this country in order that a foreign government may exploit the country. That this is the effect of Pax Britannica is gradually realized in these days. It was an unhappy circumstance that it was not realized sooner. We believed in the benevolent intentions of the Government, but in politics there is no benevolence. Benevolence is used to sugar-coat the declarations of self-interest , and we were in those days deceived by the apparent benevolent intentions under which rampant self-interest was concealed. ...... It is said there is a revival of Liberalism, but how long will it last? Next year it might be they are out of power and are we to wait till there is another revival of Liberalism... and after all what can a Liberal Government do?..... I laughed when I read the proceedings of the meeting in Calcutta congratulating people on the appointment of Mr. Morley to the Secretaryship of State for India. Passages were read from Mr. Morley’s books.... They utterly misunderstood the position or ignored the distinction between a philosopher and a statesman.....


To convert the whole electorate of England to your opinion and then to get indirect pressure to bear upon the Members of Parliament, they in their turn to return a Cabinet favourable to India and the whole Parliament, the Liberal Party and the Cabinet to bring pressure on the bureaucracy to yield - we say this is hopeless, You can now understand the difference between the Old and the New Party.... The Old Party believes in appealing to the British nation and we do not. That being our opinion, it logically follows we must have some other method........ We have come forward with a scheme which if you accept, shall better enable you to remedy this state of things than the scheme of the Old school. Your industries are ruined utterly, ruined by foreign rule, your wealth is going out of the country and you are reduced to the lowest level which no human being can occupy. In this state of things is there any other remedy by which you can help yourself? The remedy is not petitioning but boycott. We say prepare your forces, organise your power, and then go to work so that they cannot refuse you what you demand.


We have perceived one fact, that the whole of the administration, which is carried on by a handful of Englishmen, is carried on with your assistance. We are all in subordinate service. The whole government is carried on with our assistance and they try to keep us in ignorance of our power of co-operation between ourselves by which that which is in our own hands can be claimed by us and administered by us. The point is to have the entire control in our hands,


We shall not give them assistance to collect revenue and keep peace. We shall not assist them in fighting beyond the frontiers or outside India with Indian blood and money. We shall not assist them in carrying on the administration of justice. We shall have our own courts and when time comes we shall not pay taxes. Can you do that by your united efforts? If you can, you are free from tomorrow.


We have not raised this cry from a mere impulse... I do not ask you to blindly follow us. Think over the whole problem for yourselves. If you acc pet our advice , we feel sure, we can achieve our salvation thereby. This is the advice of the New Party.

【第三篇】

文章概述

作者:Claire N. Spottiswoode
題目:How Cooperation Defeats Cheats

文章大意

本篇文章的主旨是紅嘴山鴉之間的合作,對於它們遭到寄生蟲入侵的影響。文章中談到,紅嘴山鴉之間的合作和寄生蟲的入侵是相互作用的。合作容易讓它們變成寄生蟲的目標,與此同時,它們之間的合作也讓它們更容易對抗寄生蟲。在文中,作者也闡明了群體大小對於感染寄生蟲幾率的影響。越小的群體,感染幾率越大,越大的群體,感染幾率越小。在文章的最後一段,作者表明研究的結果雖然能夠說明合作對於寄生物入侵的影響,但是暫時還不能揭開紅嘴山鴉最初是如何進化出合作的特性的。

題目回顧
  • 主旨題:問作者這篇研究的目的是什麼
  • 作者文章中收集的data有什麼樣的作用?
  • 詞彙題:reflect在文中的意思。
  • 詞彙題:favor在文中的意思。
  • 獨立取證題:問那句話是文中作者提到的,群體數量對寄生物影響的證據。
  • 細節題:紅嘴山鴉在繁殖中的特點
  • 目的題:最後一段的作用
  • 圖表題:問從第一個圖表能得出什麼關於群體大小和寄生的關係。
  • 圖表題:問從圖表中能得出什麼樣的比對資訊。
  • 圖表題:問從第二個圖表中能得出什麼。
文章原文

In the spring of 1879, Hermann Lau shot two white-winged choughs, Corcorax melanorhamphos, off their nest in Queensland, Australia. He watched as additional choughs continued to attend the nest, proving that a cooperative group shared parental care ( 1). Since then, cooperatively breeding birds have had a starring role in efforts to explain the evolution of complex animal societies. We now know that “helpers-at-the-nest” who forgo reproduction are often relatives of the breeding pair. Genetic payoff is, thus, one of several advantages that helpers can gain from their superficially altruistic behavior (2). On page 1506 of this issue, Feeney et al. ( 3) show that collective defense against brood parasites (see the figure) can enhance such benefits of cooperation. Why do some bird species cooperate and others do not? Global analyses have shown that cooperative breeding (now known from 9% of species) is associated with a slow pace of life (characterized by high survival rates and low turnover of breeding territories) ( 4), monogamy (which facilitates kin selection within families) ( 5), and unpredictable environments (such as arid zones) that might favor cooperation as a bet-hedging strategy ( 6). But these factors often fail to predict the incidence of cooperation among related species or within geographical regions ( 7). Feeney et al.’s study is built on the premise that brood parasitism—reproductive cheating by species such as cuckoos and cowbirds, which exploit other birds to raise their young—is a severe selection pressure on their hosts’ breeding strategies. Parasitized parents typically not only lose their current offspring but also waste a whole breeding season raising a demanding impostor. The best way to avoid parasitism is to repel adult parasites from the nest. Feeney et al. show that sociality can be pivotal to this process. The authors begin by unfolding a new map. Using data compiled by Bird Life International, they show that the global distribution of cooperatively breeding birds overlaps strikingly with that of brood parasites. This overlap need not reflect a causal relationship:


The same unpredictable environments that favor cooperation could also favor alternative breeding strategies such as parasitism. However, the authors go on to show that even within geographical regions rich in both parasites and cooperators—Australia and southern Africa—cooperative breeders are much more likely than noncooperative species to be targeted by brood parasites.


To determine the reasons for this correlation, Feeney et al. studied cooperative breeding in superb fairy-wren (Malurus cyaneus) in Australia. Horsfield’s brood-cuckoos (Chalcites basalis) should benefit from targeting larger groups of fairy-wrens because more helpers mean faster chick growth. Yet data from a 6-year field study show that in practice, cuckoos rarely experience this advantage, because larger groups of fairy-wrens much more effectively detect and repel egg-laying intrusions by cuckoo females, mobilizing group defenses with a cuckoo-specific alarm call. Thus, cooperation and parasitism could reciprocally influence one another: Cooperators might be more attractive target because they make better foster parents, but once exploited by parasites, they are also better able to fight back, helping cooperation to persist. ( 8) Feeney et al. find that superior anti-cuckoo defenses in larger groups account for 0.2 more young fledged per season on average than smaller groups--a substantial boost given the fairy-wrens ‘low annual fecundity.


These results show convincingly that defense against brood parasites augments the benefits of helping, promoting the persistence of cooperation. But as the authors note, they cannot reveal what caused cooperation to evolve initially Brood parasitism alone cannot resolve the question of why some birds breed cooperatively. For example, cooperative kingfishers and bee-eaters are heavily parasitized in Africa but not in Australasia, showing that other advantages of helping behavior are sufficient for cooperation to persist. But we should take parasitism seriously as an important force in a cooperative life. Indeed, it may provide a mechanism contributing to the previously discovered global correlates of cooperation.(4-6)


Some insight into the likely order of evolution might come from further comparative predictions. For instance, if cooperation arose first as a defense against parasitism, cooperators may be most prevalent among hosts that rely heavily on repelling adult parasites, rather than on antiparasite strategies at later reproductive stages, such as egg or chick discrimination ( 9). In contrast, if parasites target existing cooperators because they provide superior care, this should be especially true of parasites whose chicks have the most pressing needs—for instance, those in parasitic families with large body size relative to their hosts or those whose chicks do not kill host young and therefore must share their foster parents’ care. Could there be a similar association between cooperation and parasitism among other highly social animals? Cooperation in mammals clearly persists irrespective of parasitism, given that there are no known brood-parasitic mammals (perhaps because it would be difficult for a mammal to insert live young into another’s care). But repelling parasitic egg-laying intrusions is crucial to many hosts of socially parasitic insects and has shaped sophisticated adaptations and counter defenses for and against brute force and secrecy ( 10). It will be fascinating to explore how selection for antiparasitic defense has interacted with monogamy and defensible resources as forces favoring kin-selected cooperation in invertebrates, touching on an active debate in evolutionary biology. Answers to such comparative questions will ultimately be limited by our knowledge of natural history. The work by Feeney et al. is testament to the evolution aryinsights enabled by careful long-term field studies, together with the cumulative legacy of those naturalists who made the unglamorous effort to record and publish observations of real animals in real places.

【第四篇】

文章概述

文章討論了人們對於工作截止日期的思維意識,先給出了人們做事情的四個階段,而通常人們開始工作並意識到截止日期,必須是要將任務與現在聯繫起來的時候,隨後利用到某大學研究團隊的實驗進一步闡釋,第一個實驗研究發現同年存款為截止日期比下一年存款為截止日期,更容易使人們開始開戶的行為。同樣第二個實驗驗證當截止日期和工作時間有類似特徵的時候,不容易喚醒大家開始工作的意識。隨後文章給了一個關於deadline的實驗對比圖表。

題目回顧
  • 文章主旨題
  • 資訊題:問在開始工作前人們最關注concern什麼
  • 循證題:對應前一題
  • 詞彙題:問drive的意思
  • 資訊題:問任務也很有可能被和當下聯繫起來即便在遙遠的將來
  • 循證題:對應前一題
  • 推斷題:作者提及日期的arbitrary是為了暗示什麼
  • 目的題:最後一段的作用是什麼
  • 圖表題:問哪一個值接近人們對於deadline的平均速率
  • 圖表題:問圖表與文章第一個存款實驗的區別
文章原文

If you want something done, the saying goes, give it to a busy person. It is an odd way to guarantee hitting deadlines. But a paper recently published in the Journal of Consumer Research suggests it may, in fact, be true—as long as the busy person conceptualizes the deadline in the right way.


Yanping Tu of the University of Chicago and Dilip Soman of the University of Toronto examined how individuals go about both thinking about and completing tasks. Previous studies have shown that such activity progresses through four distinct phases: pre-decision, post-decision (but pre-action), action and review. It is thought that what motivates the shift from the decision-making stages to the doing-something stage is a change in mindset.


Human beings are a deliberative sort, weighing the pros and cons of future actions and remaining open to other ideas and influences. However, once a decision is taken, the mind becomes more "implemental" and focuses on the task at hand. “The mindset towards ‘where can I get a sandwich’,” explains Ms Tu, “is more implemental than the mindset towards ‘should I get a sandwich or not?’"


Ms Tu and Dr Soman advise in their paper that "the key step in getting things done is to get started." But what drives that? They believe the key that unlocks the implemental mode lies in how people categorize time. They suggest that tasks are more likely to be viewed with an implemental mindset if an imposed deadline is cognitively linked to "now"—a so-called like-the-present scenario. That might be a future date within the same month or calendar year, or pegged to an event with a familiar spot in the mind's timeline (being given task at Christmas, say, with a deadline of Easter). Conversely, they suggest, a deadline placed outside such mental constructs (being “unlike-the-present") exists merely as a circle on a calendar, and as such is more likely to be considered deliberatively and then ignored until the last minute.


To flesh out this idea, the pair carried out five sets of tests, with volunteers ranging from farmers in India to undergraduate students in Toronto. In one test, the farmers were offered a financial incentive to open a bank account and make a deposit within six months. The researchers predicted those approached in June would consider a deadline before December 31st as like-the-present. Those approached in July, by contrast, received a deadline into the next year, and were expected to think of their deadline as unlike-the-present. The distinction worked. Those with a deadline in the same year were nearly four times more likely to open the account immediately as those for whom the deadline lay in the following year. Arbitrary though calendars may be in dividing up time's continuous flow, they influence the way humans think about time.


The effect can manifest itself in even subtler ways. In another set of experiments, undergraduate students were given a calendar on a Wednesday and were asked to suggest an appropriate day to carry out certain tasks before the following Sunday. The trick was that some were given a calendar with all of the weekday colored purple, with weekends in beige (making a visual distinction between a Wednesday and the following Sunday). Others were given a calendar in which every other week, Monday to Sunday, was a solid color (meaning that a Wednesday and the following Sunday were thus in the same week, and in the same cooler). Even this minor visual cue affected how like- or unlike-the-present the respondents tended to view task priorities.


These and other bits of framing and trickery in the research support the same thesis: that making people link a future event to today triggers an implemental response, regardless of how far in the future the deadline actually lies. If the journey of 1,000 miles starts with a single step, the authors might suggest that you take that step before this time next week.

【第五篇】

文章概述

題目:Ancient magma plumbing found buried below moon’s largest dark point
作者:Eric Hand
2014 American Association for Advanced Science

文章大意

月球最大的圓形暗點oceanus procellarum下面找到了長方形的地貌,有冷卻的岩漿等痕跡,很像地球的裂谷rift valley,證明月球很久以前也是有地址和岩漿活動的。OP這個暗點原來認為是隕石撞擊造成的盆地,但是長方形地貌的發現反駁了這個idea,因為盆地不可能有棱角。
NASA發射了一對飛船GRAIL可以採集地貌細微的變化以及分析密度,提供了資訊給Hannah Andrews這個科學家和她的團隊。
OP這個暗點地區有大量的輻射粒子,可以釋放大量的熱量。在冷卻之後,地殼會開裂,地幔中的岩漿會溢出來,然後慢慢的形成了暗點,多出來的岩漿冷卻後加大了該地區的重量,導致下沉形成盆地狀的地貌。
宇宙中有很多相似的情況,作者距離了一些,比如土星的衛星。最後另一個科學家表揚了Hannah團隊的貢獻,但是仍舊問題沒解決,比如為什麼卻只有進地球的一側出現了OP和長方形地貌,而月球其他的地方雖然有相似的條件卻沒有這種地貌。

題目回顧
  • 全文的主要目的是什麼? 選擇月球上新的發現質疑之前的假設理論
  • 為什麼作者說發現新的長方形地貌的時候,還要提及 geologic plumbing system?是為了進一步說明該地域的地址形態
  • Hannah是如何評價之前的隕石撞擊導致盆地理論的
  • NASA飛船GRAIL給Hannah團隊提供了什麼樣的幫助
  • GRAIL提供的資訊和什麼有關
  • Hannah對於資訊後的分析如何評價
  • 循證題
  • 結合以上內容,Dark Spot到底應該是如何形成的
  • 為什麼一開始認定OP是隕石衝擊形成的
  • 循證題
  • 作者為什麼給出宇宙中一些其他天體的例子,比如土星的衛星
文章原文

Ancient magma plumbing found buried below moon's largest dark spot
By Eric Hand Oct. 1, 2014 , 1:00 PM


Scientists have found a nearly square peg underneath a round hole—on the moon. Several kilometers below Oceanus Procellarum, the largest dark spot on the moon’s near side, scientists have discovered a giant rectangle thought to be the remnants of a geological plumbing system that spilled lava across the moon about 3.5 billion years ago. The features are similar to rift valleys on Earth—regions where the crust is cooling, contracting, and ripping apart. Their existence shows that the moon, early in its history, experienced tectonic and volcanic activity normally associated with much bigger planets.


“We’re realizing that the early moon was a much more dynamic place than we thought,” says Jeffrey Andrews-Hanna, a planetary scientist at the Colorado School of Mines in Golden and lead author of a new study of the Procellarum’s geology. The discovery also casts doubt on the decades-old theory that the circular Procellarum region is a basin, or giant crater, created when a large asteroid slammed into the moon. “We don’t expect a basin rim to have corners,” Andrews-Hanna says.


The work is based on data gathered by GRAIL (Gravity Recovery and Interior Laboratory), a pair of NASA spacecraft that orbited the moon in 2012. Sensitive to tiny variations in the gravitational tug of the moon, GRAIL mapped density variations below the surface (because regions of higher density produces lightly higher gravitational forces). Below known impact basins, GRAIL found the expected ring like patterns, but underneath the Procellarum region, the mysterious rectangle emerged. “It was a striking pattern that demanded an explanation,” Andrews-Hanna says.


Scientists already know that the Procellarum region is rich in radioactive elements that billions of years ago would have produced excess heat. The study team theorizes that as this region cooled, the rock would have cracked in geometrical patterns, like honeycomb patterns seen on Earth in basalt formations, but on a much larger scale. In a study published today in Nature, the researchers propose that these cracks eventually grew into rift valleys, where magma from the moon’s mantle welled up and pushed apart blocks of crust. Lava spilled out and paved over the Oceanus Procellarum, creating the dark spot that is seen today. The extra weight of this dense material would have caused the whole region to sink slightly and form the topographic low that has made the Procellarum seem like a basin.


With the discovery, the moon joins Earth, Mars, and Venus as solar system bodies with mapped examples of rifting. There are also similar features near the south pole of Enceladus, the moon of Saturn that is spewing water into space from cracks in an ice shell.


Andrews-Hanna and colleagues have made a good case, says Herbert Frey, a planetary scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, even though the newly described features are surprising. The moon is not big enough to have the same strong convective cooling process that Earth has in its interior, he explains, and ordinarily convection is one of the main mechanisms thought to lead to large-scale rifting. So just what caused the rifting remains unclear. “It just means the moon continues to surprise us,” he says. Frey adds that a remaining mystery is why the rectangular features were found only beneath Oceanus Procellarum. Even if the rifting is explained by the excess radioactive elements, there is still no definitive explanation for why only the near side of the moon ended up enriched.


The discovery could also be a death knell for the impact theory for Oceanus Procellarum, an idea first put forth in the early 1970s. A basin there would have been the largest on the moon—larger than the South Pole–Aitken Basin—and second in the solar system only to the Borealis Basin on Mars, which covers the planet’s entire northern hemisphere.


Ryosuke Nakamura, a researcher at the National Institute of Advanced Industrial Science and Technology in Tsukuba, Japan, is still not convinced that an impact can be ruled out. In 2012, he and his colleagues published a paper in Nature Geoscience that found compositional evidence for an impact within Procellarum—a type of pyroxene mineral that is found in other, known impact basins such as South Pole–Aitken and is associated with the melting or excavation of mantle rock from an asteroid impact.


In response to the current study, Nakamura says that the features in the southwestern corner of the Procellarum region look to be circular rather than rectangular, and still consistent with an impact. But Frey, who has long been skeptical of the impact theory, says that the features are as clear as day, and not what you’d expect underneath a basin. “That looks like a rectangle to me.”




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