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
2021-09-17
26
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 which matter 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.
Galileo Galilei’s experiment at the Tower of Pisa around 400 years ago
选项
A、was one way of testing Einstein’s general theory of gravity.
B、illustrated the insignificance of mass and composition of an object.
C、acted as a well-known example to testify the equivalence principle.
D、showed that all objects on Earth were influenced by gravity.
答案
C
解析
根据Galileo Galilei和400 years ago定位到第三段。其中提到大约400年前伽利略在比萨斜塔的著名实验证明了等效原理,C项与此意相同。
转载请注明原文地址:https://kaotiyun.com/show/x41Z777K
0
考研英语一
相关试题推荐
【F1】Americansnolongerexpectpublicfigures,whetherinspeechorinwriting,tocommandtheEnglishlanguagewithskillandg
ThewordRenaissancehasoflateyearsreceivedamoreextendedsignificancethanthatwhichisimpliedinourEnglishequivalen
BernardBailynhasrecentlyreinterpretedtheearlyhistoryoftheUnitedStatesbyapplyingnewsocialresearchfindingsonthe
BernardBailynhasrecentlyreinterpretedtheearlyhistoryoftheUnitedStatesbyapplyingnewsocialresearchfindingsonthe
Scientistsaresupposedtochangetheirminds.【F1】Havingadoptedtheirviewsonscientificquestionsbasedonanobjectiveeval
Twenty-sevenyearsago,EgyptreviseditssecularconstitutiontoenshrineMuslimshariaas"theprincipalsourceoflegislation
【F1】Duringthepastgeneration,theAmericanmiddle-classfamilythatoncecouldcountonhardworkandfairplaytokeepitself
Researchhasshownthat—inbothsexesandacrossnumerouscultures—attractivepeoplearejudgedtobesmarter,kinder,morehone
Expressionismisanartisticstyleinwhichtheartistseekstodepictnotobjectiverealitybutratherthesubjectiveemotions
Expressionismisanartisticstyleinwhichtheartistseekstodepictnotobjectiverealitybutratherthesubjectiveemotions
随机试题
把下段文章中画线的句子译成现代汉语。管仲夷吾者,穎上人也。少時常與鮑叔牙游,鮑叔知其賢。管仲貧困,常欺鮑叔,鮑叔終善遇之,不以為言。已而鮑叔事齊公子小白,管仲事公子糾。及小白立,為桓公,公子糾死,管仲囚焉。鮑叔遂進管仲。管仲既用,任政於齊,齊桓公
Today,mostcountriesintheworldhavecanals.Manycountrieshavebuiltcanalsnearthecoast,andparallel【C1】______thecoast
HTTP协议采用()方式传送Web数据。
在病例对照研究中,控制混杂偏倚,不应采取下列哪条措施
根据1954年宪法和现行宪法有关立法的规定,下列哪项是正确的?()
一个由R=3Ω、L=4H和C=1μF三个元件相串联的电路,若电路振荡,则振荡角频率为下列选项中的()。
[2006年第33题]在双缝装置实验中,对于给定的入射单色光,当双缝间距增大时,则屏幕上干涉条纹的变化情况是()。
( )负责对基金管理公司的会计核算结果进行复核。
不积跬步,无以至千里,不积小流,无以成江河,这段话说明的是()。
Asociety’sinfantmortalityrateisanacceptedindicatorofthatsociety’sgeneralhealthstatus.Eventhoughinsomelocaliti
最新回复
(
0
)