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
考研
Familiar as it may seem, gravity remains a mystery to modern physics. Despite several decades of trying, scientists have failed
Familiar as it may seem, gravity remains a mystery to modern physics. Despite several decades of trying, scientists have failed
admin
2015-06-24
63
问题
Familiar as it may seem, gravity remains a mystery to modern physics. Despite several decades of trying, scientists have failed to fit Einstein’s general theory of relativity, which describes how gravity holds big objects together, with the quantum mechanics (an extension of statistical mechanics based on quantum theory) he pioneered, which describes the tiny fundamental particles of whichmatter consists and the forces by which they interact.Recent discoveries have highlighted further problems.
Many physicists are therefore entertaining the idea that Einstein’s ideas about gravity must be wrong or at least incomplete. Showing exactly how and where the great man erred is the task of the scientists who gathered at the "Rethinking Gravity" conference at the University of Arizona in Tucson this week.
One way to test general relativity is to examine ever more closely the assumptions on which it rests, such as the equivalence principle: that gravity accelerates all objects at the same rate, regardless of their mass or composition. This principle was famously demonstrated by Galileo Galilei some 400 years ago when he simultaneously dropped cannon and musket balls, and balls made of gold, silver and wood, from the Tower of Pisa. Each appeared to hit the ground at the same time.
A more precise test requires a taller tower. In effect, researchers are sending balls all the way to the moon and back. Tom Murphy, of the University of California, San Diego, and his colleagues fire laser beams from the deserts of New Mexico at reflectors placed on the moon by American and Russian spacecraft in the late 1960s and early 1970s. They use a telescope to capture the small fraction of the light that returns. Because the speed of light is known, they can calculate the distance between the Earth and the moon from the time taken for light to pass through it.
According to general relativity, because the Earth and the moon orbit the sun, they should "fall" towards it at the same rate, in the same way as Galileo’s balls fell to the ground. By repeatedly measuring the distance between them, scientists can calculate the orbits of the Earth and the moon around the sun relative to each other. If the equivalence principle were violated, the moon’s orbit around the Earth would not appear straight, either towards or away from the sun So far, Dr Murphy told the conference, these experiments have merely confirmed the equivalence principle to one part in 10 trillion. Dr Murphy and his colleagues hope that even more precise measurements could ultimately show general relativity to be only approximately correct. This would usher in a new revolution in physics.
What can we infer from the last paragraph?
选项
A、General relativity is actually ungrounded at all.
B、The calculation of the orbits shows that equivalence principle is violated
C、More should be done to prove the correctness of equivalence principle.
D、A new revolution in physics has already arrived.
答案
C
解析
推理判断题。最后一段中作者指出现代科学家所做的试验“仅仅在10万亿分之一的概率上证实了等效原理”,也就是说还需要更多试验来检验该理论,C项与之相符。A项文中并未提到,属凭空臆测;文中只说到“通过反复不断地测量地月之间的距离,科学家可以计算出地球和月球相对彼此围绕太阳公转的轨道”并没有说“计算绕转轨道说明等效原理被违背”,故B项错误;D项对文章末句理解错误,该变革还没发生。
转载请注明原文地址:https://kaotiyun.com/show/Dy74777K
0
考研英语一
相关试题推荐
HowtoSolvetheProblemofChildhoodObesityintheUnitedStatesTheproportionofchildreninAmericawhoareoverweight
Whenspeakingaboutsciencetoscientists,thereisonethingthatcanbesaidthatwillalmostalwaysraisetheirindignation,
Thesuccessstoryoftopinvestorsandexecutivesisastapleofbusinessbooksandmagazines.【C1】______researchsuggestswesho
Whileyouenjoythesunlight,itcastsyourshadowontheground.Therehasbeenadiscussionrecentlyontheissueinanewspap
TheAmericaneconomyisgrowing,accordingtothemostrecentstatistics,atthehighrateof7%,andisinthemiddleofthel
Anyonewhodoubtsthatglobalfinancialmarketscontrolnationaleconomiesneedonlylookatthecrisisfacingthe"tigers"oft
Overthepastcentury,allkindsofunfairnessanddiscriminationhavebeencondemnedormadeillegal.【F1】Butoneinsidiousform
Ifthereisonecentral,recurringmistaketheUnitedStatesmakeswhendealingwiththerestoftheworld,itistoassumethat
Lifeisunfair,aseventheBibleacknowledges.Wecan’tallhitabaseballlikeDiMaggioorsingliketheBeatles.Buthowmuch
Biographiescanbewearisomecontrivances,oftentoolongandtoodetailedfortheirowngood.Biographersmakethemistakeofs
随机试题
三个中国学生张林、赵强、李珊和三个外国留学生约翰、杰西、安娜暑假外出旅游,可供选择的旅游地有西安、杭州、大连和张家界。已经知道:(1)每人只能去一个地方。(2)凡是有中国学生去的地方,就必须有外国留学生去。(3)凡是有外国留学生去的地方,就必须有中国
女之耽兮,不可说也。
可疑肉毒毒素中毒的患者,分离病原菌主要采集的标本是
男,45岁。因息严重精神分裂症,用氯丙嗪治疗,两年来用的氯丙嗪量逐渐增加至600mg/d,才能较满意的控制症状,但近日出现肌肉震颤,动作迟缓,流涎等症状,对此,应选何药纠正
检测机构试验检测机构不能直接申请公路工程专项类等级。()
关于二级注册建筑师执业印章的使用效力,以下()解释是不正确的。
甲企业为增值税一般纳税人,适用增值税税率为17%,原材料按实际成本核算,2016年12月初,A材料账面余额90000元.该企业12月份发生的有关经济业务如下:(1)5日,购入A材料1000千克,增值税专用发票上注明的价款300000元,增值税税额510
下列语句与出处对应错误的是:
方程有解.(1)a≤0(2)0<a<10
小蒋是一位中学教师,在教务处负责初一年级学生的成绩管理。由于学校地处偏远地区,缺乏必要的教学设施,只有一台配置不太高的计算机可以使用。他在这台计算机中安装了MicrosoftOffice,决定通过Excel来管理学生成绩,以弥补学校缺少数据库管理系统的不
最新回复
(
0
)