共查询到20条相似文献，搜索用时 15 毫秒
1.
In Part I1 of this article we learnt that there are compelling evidences from dynamics of spiral galaxies, like our own, that there must be non-luminous matter in them. In this second part we will see that even clusters of galaxies must harbour dark matter. As if this was not enough, it turns out that if our knowledge of the universe is not completely wrong, then the universe as a whole has to contain dark matter and that it must be of some exotic type. 相似文献
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Biman Nath 《Resonance》2009,14(3):226-235
Soon after the discovery that we live in a separate galaxy and that there are many other galaxies in the universe, Hubble
designed a classification scheme of galaxies based on their appearances. It was such a robust scheme that it continues to
be one of the basic tools of modern astronomy, and motivates astronomers to look for connections between different types of
galaxies. 相似文献
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空间概念是物理学的最基础概念之一,对空间性质的认识随科学发展逐渐清晰,而对空间内在本质的认识却一直是争论与模糊的。对宇宙膨胀、卡西米尔效应、量子场论的真空能量,以及星系的核聚变等进行了综合分析：空间是由物质转化而来,空间与物质是同质的;物质与空间之间存在相互转换关系,物质可转化成空间,空间可转化为物质;空间不是物质的属性,而是物质的另一种特殊形态;空间是客观实在、独立存在的,但其性质不是牛顿绝对空间的几何不变,而是与物质或运动相互作用,与广义相对论的空间几何特性一致。同时又结合宇宙背景辐射光子数密度、核聚变反应的光子产生比率,计算出了物质与空间转换关系的转换系数。 相似文献
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J. S. Bagla 《Resonance》2009,14(3):216-225
Hubble’s name is associated closely with the idea of an expanding universe as he discovered the relation between the recession
velocity and the distances of galaxies. Hubble also did a lot of pioneering work on the distribution of galaxies in the universe.
In this article we take a look at Hubble’s law and discuss how it relates with models of the universe. We also give a historical
perspective of the discoveries that led to the Hubble’s law. 相似文献
5.
任海涛 《楚雄师范学院学报》2011,26(3):37-42
由星系团的运行速度观测而推测出来的宇宙中含有大量暗物质的理论似乎获得了大部分物理学界和天文学界的人的认同。而我却不认同此理论,因为事实上并不存在大量的暗物质,只要将整个星系的各个恒星对星系边沿的恒星的万有引力重新逐个计算并统计引力效应就能得到边沿恒星绕行所需要的引力值。使得万有引力的增大的原因在于临边陡增效应和力桥效应,并由此提出了万有引力新的表述。 相似文献
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Roddam Narasimha 《Resonance》2005,10(8):67-79
You look up at the sky, and see a lovely cloud; you look down, and may see lovely ripples on a rivulet (or river). On a hot summer afternoon you see dancing dust devils; on a cold winter evening you can see smoke rising lazily from achulah, and hang up there as if it has given up. You peer at a telescope, and see intense supersonic jets, or vast whirling galaxies; you measure in a wind tunnel, and sense powerful tornadoes behind an aircraft wing. The universe is full of fluid that flows in crazy, beautiful or fearsome ways. In our machines and in the lab, as in terrestrial nature, one sees this amazing diversity in the flow of such a simple liquid like water or a simple gas like air. What is it that makes fluid flows so rich, so complex-some times so highly ordered that their patterns can adorn a saree border, sometimes so chaotic as to defy analysis? Do thesame laws governall that extraordinary variety? We begin with a picture gallery of a number of visible or visualized flows, and consider which ones we understand and which ones we do not, which ones we can compute and which ones we cannot; and it will be argued that behind those all-too-common but lovely flows lie deep problems in physics and mathematics that still remain mysteries. 相似文献
9.
Soon after the discovery of the expansion of the universe, astronomers hoped to determine the parameters of the universe by
comparing distant galaxies with nearby ones. Observing distant galaxies, however, meant observing them as they were long ago.
A crucial assumption in these studies was that galaxies hardly change, in the time scale of the expansion of the universe.
Beatrice Tinsley was one of the first astronomers to point out that galaxies do change. Here we discuss a simplified model
of galactic evolution, and show that the comparison of its prediction with observations uncovers clues to how galaxies evolve
with time 相似文献
10.
引力透镜效应已经成为当前探测宇宙中物质分布最有效的工具之一,因其光线偏折不依赖于物质的组分和状态,所以它很适合于探测包括暗物质在内的所有物质在宇宙中的分布.在引力透镜效应的提出及发现基础上,根据引力透镜的分类,分述了强引力透镜、弱引力透镜和微引力透镜,并讨论了引力透镜效应在宇宙学中的应用. 相似文献
11.
Max Yalden 《Interchange》1978,9(4):4-10
Conclusion In this brief look at French-language instruction in Canada, I have tried to consider a number of possible approaches to the problem. My emphasis has been on the pragmatic and the practical because I believe that Canadians need to look at the matter in this way and not in overblown emotional terms.Providing solid French language programs throughout our school system is not a frill. It is the basic option that we must offer our children if we want them to have the fullest opportunity to participate in Canadian life. 相似文献
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Biman Nath 《Resonance》2007,12(11):44-53
Part 11 of the article discussed the discovery and observed properties of cosmic ray particles. These energetic particles are produced
during violent astronomical events. We discuss possible sources of cosmic rays detected on Earth in this article. Supernovae
explosions of dying stars are believed to produce cosmic rays with low energy. The detection of ultra-high energy cosmic rays
is however difficult to explain. On one hand, they must originate outside our Galaxy and on the other, the cosmic microwave
background radiation pervading the universe makes it difficult for them to travel large distances in intergalactic space.
So, they must be produced in the neighbourhood of our Galaxy, but are there enough energetic phenomena taking place in this
region of the universe?
Biman Nath is an astrophysicist at the Raman Research Institute, Bangalore. 相似文献
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Jayant V. Narlikar 《Resonance》1996,1(2):12-17
The expansion of the universe was established based on observations made in the 1920’s, of the Doppler shift of light from galaxies. The proportionality between velocity and distance is the famous Hubble Law. Simplified mathematical models of the universe are based on the idea, which is supported by observations, that there are no preferred locations or directions in space. 相似文献
16.
孔子说自己的道是一以贯之的,却并没有明确说自己的这个＂道＂到底是什么,又是用什么贯串起来的。后人恰恰多就这两个问题各持己见,争论不已。关于孔子的＂道＂,有三种较为普遍的看法,即＂仁＂、＂礼＂、＂仁与礼＂;关于＂一以贯之＂的＂一＂,有的认为是＂忠恕＂（这种说法较为普遍）,有的认为是＂中庸＂,也有的认为是＂仁＂,还有的认为是＂礼＂。不管哪种说法,要搞清孔子之道一以贯之的＂一＂是什么,如果从孔子生活的时代、孔子的人生理想、孔子中庸思想的形成、孔子的人生实践来分析其思想观念,就会明白,＂中庸＂应该是孔子之道＂一以贯之＂的方法。 相似文献
17.
商忠 《新乡师范高等专科学校学报》2006,20(1):127-129
当前中国的语言文字学界,普遍采用西方有关的文字定义,即“文字是记录语言的书写符号”,这个定义只概括了汉字的一种作用,一种特性,它远远涵盖不了汉字全部。其实,我国汉朝的许慎早就为汉字作了义界,对其义界运用训诂的方法加以阐微,可以得出这样的结论:在许慎看来,文字的发明创造,是对天地万物与人事的标指。也就是说,汉字不仅是语言的记录符号,而且也是对生生大千、历历人事的反映,是对宇宙秩序的规定。 相似文献
18.
Jayant V. Narlikar 《Resonance》2005,10(12):6-11
The expansion of the universe was established based on observations made in the 1920’s, of the Doppler shift of light from
galaxies. The proportionality between velocity and distance is the famous Hubble Law. Simplified mathematical models of the
universe are based on the idea, which is supported by observations, that there are no preferred locations or directions in
space. 相似文献
19.
Jayant V. Narlikar 《Resonance》1996,1(1):7-13
The first part of this series covers the historical background to the subject of cosmology-the study of the structure and evolution of the whole universe. Ancient ideas, such as those of the Greeks, already show the beginnings of attempts to account for observations by natural laws, and to prove or disprove these by other observations. It needed the invention of the telescope and studies by scientists like Herschel and Hubble to reach the current understanding of our place in our galaxy, and its place as only one member of a far larger collection of galaxies which fill the observable universe. 相似文献
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Berry Billingsley Keith Taber Fran Riga Helen Newdick 《Research in Science Education》2013,43(4):1715-1732
A number of previous studies have shown that there is a widespread view among young people that science and religion are opposed. In this paper, we suggest that it requires a significant level of what can be termed “epistemic insight” to access the idea that some people see science and religion as compatible while others do not. To explore this further, we draw on previous work to devise a methodology to discover students’ thinking about apparent contradictions between scientific and religious explanations of the origins of the universe. In our discussion of the findings, we highlight that students’ epistemic insight in this context does seem in many cases to be limited and we outline some of the issues emerging from the study that seem to boost or limit students’ progress in this area. 相似文献