首页
登录
职称英语
It is hardly surprising that something called dark energy is hard to study.
It is hardly surprising that something called dark energy is hard to study.
游客
2023-09-09
49
管理
问题
It is hardly surprising that something called dark energy is hard to study. It is important, though. If it exists at all, it makes up about three-quarters of the stuff in the universe. And if it does not exist, then existing theories of physics will have to be useless.
The latest evidence that dark energy really does exist was produced on December 16th by Alexey Vikhlinin, of the Smithsonian Observatory in Cambridge, Massachusetts, and his colleagues. They used an orbiting X-ray telescope called Chandra to study the way that groups of galaxies grow. They discovered that this growth is restrained in exactly the way that dark-energy theory predicts.
The idea of dark energy was dreamed up ten years ago, to explain why the expansion of the universe that began with the Big Bang seems to be accelerating, rather than slowing down. That unexpected finding was the result of studies of supernovas (超新星) whose apparent brightness (and therefore distance) did not match the previous theory. Dark energy causes the acceleration by pushing space itself apart, altering the distances to the supernovas as it does so.
Dark energy is also a convenient explanation for another curiosity. Geometrically, space is flat. For it to be held that way, rather than getting more and more curved over time, the amount of matter and energy it contains must be at a particular, critical density. Without the dark energy needed to explain the acceleration, the universe would have only a quarter of the necessary density. It is therefore a relief that Dr Vikhlinin’s results agree with the theory: the pushing apart of space that dark energy causes makes it harder than it otherwise would be for galactic clusters(银河星团) to grow.
This result does not bring physicists much closer to understanding what dark energy actually is. The favored explanation is the so-called universal constant -- an as-yet-unobserved consequence of the general theory of relativity. But that theory predicts a force far more powerful than the one actually seen. So the truth is that physicists are still in the dark. [br] Where did the physicists get the fact that universe expansion is accelerating?
选项
答案
groups of galaxies grow.
解析
由定位句可知,物理学家研究超新星时得到了这一出乎意料的发现。又根据句中指示代词“that”的指代关系,可知“出乎意料的发现”是指宇宙扩张速度加快,从而推知研究学家们是通过对超新星的研究发现宇宙扩张在加速这一事实的,故本题答案是From the result of studies of supernovas。
转载请注明原文地址:https://tihaiku.com/zcyy/2997745.html
相关试题推荐
Drunkendriving—sometimescalledAmerica’ssociallyacceptedformofmurder—
Drunkendriving—sometimescalledAmerica’ssociallyacceptedformofmurder—
Drunkendriving—sometimescalledAmerica’ssociallyacceptedformofmurder—
Drunkendriving—sometimescalledAmerica’ssociallyacceptedformofmurder—
Drunkendriving—sometimescalledAmerica’ssociallyacceptedformofmurder—
Drunkendriving—sometimescalledAmerica’ssociallyacceptedformofmurder—
AimlessnesshashardlybeentypicalofthepostwarJapanwhoseproductivity
[originaltext]M:Ijustcalledthetravelagency,it’sallset.OnJunefirst,
[originaltext]M:Ijustcalledthetravelagency,it’sallset.OnJunefirst,
[originaltext]M:Ijustcalledthetravelagency,it’sallset.OnJunefirst,
随机试题
Thereare______inthesea.[br][originaltext]Therearemanyislandsint
清热泻火,利水通淋的方剂是( )。A.二妙散 B.茵陈蒿汤 C.三仁汤
有关肠杆菌科的特性中,哪一项不正确A.为革兰阳性杆菌或球杆菌B.为机会病原菌C.
共用题干 江先生与张小姐2000年相识,并于2001年2月1日登记结婚,200
从所给的四个选项中,选择最合适的一个填入问号处,使之呈现一定的规律性: A.如
借款人在偿还个人住房贷款时,贷款支付方式可以同时采取委托扣款和柜面还款两种方式。
长期服用糖皮质激素的患者宜多食用的是A.绿叶蔬菜 B.咖啡 C.葡萄柚汁
男,57岁。拟诊为右三叉神经痛。对鉴别原发、继发三叉神经痛最有意义的检查结果是A
下列变量取值中,相关的程度最高的是()。A.0.82 B.-0.93 C.
根据《声环境质量标准》,关于噪声敏感建筑物监测的说法错误的是( )。A.不得不
最新回复
(
0
)