“宇宙有限”的唯心论观点必须批判

在宇宙无限还是有限的问题上,唯物论与唯心论、辩证法与形而上学的斗争一直贯串着整个物理学史。唯物论认为宇宙是无限的,唯心论则主张宇宙是有限的。在物理学发展的每一阶段,这两条哲学路线之间都进行着激烈的斗争。尽管物理学的发展总是证明了宇宙有限论的失败,但是伴随着科学的进步,唯心论者总要歪曲和利用当时物理学的最     

暴涨——宇宙年少时

热大爆炸宇宙学的成功：宇宙学的标准模型 工业上一种产品的成功,莫过于成为业界的标准。同样地,科学中一个理论的成功,莫过于被誉为标准模型。热大爆炸宇宙学,正是这样一个标准模型。在介绍今天故事的重点——暴涨之前,让我们回顾一下,作为现代宇宙学的标准模型,热大爆炸宇宙学,如何描述宇宙的现状、过去和未来。我们的宇宙,从诞生至今,已经有137亿岁了。这相当于人类几千年文明史的几百万倍。宇宙浩瀚无垠,当今科学尚不能确定整个宇宙空间的大小,是有限还是无限。然而,我们能观测到的宇宙总是有限的。     

自然辩证法讲座:第七讲 学习《力学和天文学》

一、批判力学中的形而上学观点, 阐明辩证思维的必要性 力学部分札记,是恩格斯在1873至1875年间写的.在这五个札记中,恩格斯依据当时的科学资料,尖锐地批判了力学中的形而上学观点以及唯心主义错误,阐明了有关问题的辩证性质.1.力学定律的条件性、近似性 毛主席教导我们说:“马克思主义者承认,在绝对的总的宇宙发展过程中,各个具体过程的发展都是相对的,因而在绝对真理的长河中,人们对于在各个一定发展阶段上的具体过程的认识只具有相对的真理性”1).自然科学的定律和范畴,是人类对自然规律的反映.“规律”的概念,是人类对客观现象和过程之…     

“色即是空”的物理学解析

我们人类能够感知到的这个宇宙是有限的,这一点在科学界已经无可置疑,因为宇宙在时间上是有限的,形成已有大约150亿年的时间,那么它在空间上也必然是有限的.2008年2月哈勃望远镜拍摄到距地球130亿光年的最远星系,科学家称这些星系已经很接近宇宙的边缘,宇宙的边缘距离地球约为150亿光年(150亿光年的距离和150亿年的形成时间似乎是一个巧合).     

宇宙节点和万物之源

 自古至今,我们生活的这个世界,有着无穷无尽的景象,从而使得人类对其产生浓厚的兴趣和无限的遐想。宇宙的运动规律到底是什么样,经过千百年探索和研究,人类对宇宙有了初步的了解和认识。从本质上讲,整个宇宙是由物质组成的,没有物质的真空不存在。整个宇宙中所有物质以运动的形式存在着。这些物质随着时间的推移,在一定宇宙条件下会不断产生和灭亡。原子经过自发裂变和感生裂变以及核聚变反应之后,从而产生新的其他原子和粒子;在一定条件下,光子将自身的能量传递给金属中的电子,使其脱离金属束缚后变为自由电子飞离金属;对于恒星来说,经过引力收缩阶段后,内部开始热核反应.     

20世纪科技发展的一、二、三、四

 20世纪已落下了帷幕,回眸100年,人类在科学发展的道路上经历了艰苦卓绝的探索研究和奋斗,以自己的理性和智慧创造出了前所未有的辉煌,科学和技术在各方面取得了惊人的成果。“一台电脑”带来信息化时代“两大理论”从根本上改变了人类对世界的认识以“三大工程”为代表的高新技术,显示了科学对人类生活世界的重新改造和塑造的能力“四大模型”是以物理学革命为先导的理论自然科学的主要成就,使人类对宇宙和生命的认识更加深化。科学给人类带来物质文明和精神文明,开创了一个新时代。     

人类认识宇宙的足迹

人类认识宇宙经历了漫长的过程。天文学的不断发展对于历代哲学和科学技术的进步不断提出挑战。宇宙是怎样起源和演化的？宇宙的结构究竟如何？我们的宇宙将来结局如何甲这些仍然是现代宇宙学面临的课题。为了理解现代宇宙学,在这期彩色插页里,我们以一些精彩的画面回眸一下人类探索宇宙的历程,或许可以使我们更好地认识和理解宇宙学最新的发展方向。     

“宇宙与生命”讲座之四——宇宙之大

我们的万物图中,标定了宇宙有大小,为137亿光年,于是一切事物都划定在一个有限的区域内了。这个数字是什么意义？怎么来的？很有必要解释一下,这是我们宇宙观的基石。137亿光年,其实只是我们今天的宇宙的“哈勃半径”,与宇宙的膨胀率有关。宇宙的尺度是随宇宙年龄的增加而膨胀的。人类的科学史观中,没有什么概念比宇宙膨胀更为重要的了,它比“一切由原子构成”的原始观念更为影响深远和更让人始料不及。我们人类居住在地球上,地球只是太阳系的八大行星之一。而像太阳这样或大或小的恒星,在银河系中有千亿个,     

人类文明的发展和宇宙演化

生命现象是自然界中物质运动的形式之一,人类是生命现象的杰出代表,从某种意义上来说,人类的一切活动也都是自然界物质运动的一部分。因此,我们在研究宇宙的演化时,应该把以人类为代表的生命现象这一物质运动形式所产生的影响考虑进去,可是,到目前为止,很多人在研究宇宙演化时都没有考虑这一因素。之所以如此,可能是由于这样几个原因: 首先,人们认为:人的寿命非常短暂,现在人的平均寿命不到一百年,跟宇宙的演化时间已有约200亿年相比,太短暂了;其次,人类的活动范围太小了,人类的足迹至今只踏上了月球,这跟整个宇宙空间相比是那样的微不足道,使人们感到人类的活动对宇宙的演化似乎没有丝毫的影响;第三,人们可能认为生命现象只是宇宙演化过程中一种特殊的、暂时的现象,因而在研究宇宙的演化时可以忽略这一因素;第四,在考虑问题时,人们往往无意之中把自己排除在自然之外,故而把宇宙的演化作为所谓客观现象加以研究而忘记了人类自己也是宇宙的一部分。 如果我们从生命现象在宇宙中的普通性、从生命现象的发展变化的角度看,结果又将会是怎样的?根据天文观测和统计规律,不少科学家早就断言:在宇宙中,跟太阳、地球情况类似的星球其数量是非常可观     

带着激情、精确和耐心的奋进号——丁肇中先生谈Alpha 磁谱仪

 Alpha 磁谱仪(AMS)于2011 年5 月20 日在美国佛罗里达州的肯尼迪航天中心由奋进号航天飞机发射升空。发射前,在肯尼迪航天中心的报告厅举行的新闻发布会上,AMS 的首席科学家丁肇中先生对听众作了简单的情况介绍。他的实验马上要由奋进号航天飞机发射升空,然后,安装在国际空间站(International Space Station, ISS)上。丁肇中先生说:“到目前为止,人类对宇宙的认识大都来自可见光的测量。除可见光之外,还有带电粒子,但人类很少利用带电粒子来研究宇宙。”“AMS 探测器是人类第一个直接在宇宙空间探测宇宙线中的带电粒子的探测器。人类第一次将带有磁铁的探测器发射到宇宙空间中。这个探测器将工作20 年,也就是与国际空间站的寿命相同。这是在宇宙空间工作的唯一的基本科学实验。”     

Theory of a gauged gravitational field with localization of the Einstein group

A theory of a gauged gravitational field with localization of the group of motions of a homogeneous static Einstein universe (Einstein group R x SO(4)) is formulated. Starting from the tetradic components of Einstein's universe, a relationship is established between the Riemannian metric and the gauge fields of Einstein's group. The metric connection with torsion, transforming when the gauge fields are switched off into the Christoffel connection of Einstein's universe, is found. It is shown that in the limit of infinite radius of curvature of Einsteinr's universe, the given Einstein-invariant gauge theory transforms into the tetradic theory of gravitation with localized triadic rotations. Exact solutions are obtained in the form of nonsingular cosmological models.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 68–73, July, 1985.     

Cosmological term in the general theory of relativity and localization of the de Sitter and Einstein groups

The theory of a gauge gravitational field with localization of the de Sitter group is formulated. Starting from the tetradic components of the de Sitter universe, a relationship is established between the Riemannian metric and the de Sitter gauge field. It is shown that the general theory of relativity with the cosmological term is the simplest variant of the de Sitter gauge theory of gravitation, which transforms in the limit of an infinite radius of curvature of the de Sitter universe into the Poincaré-invariant GTR without the cosmological term. A theory of a gauge gravitational field with localization of Einstein's group of motions of the uniform static universe (the Einstein group R × S0 (4)) is formulated in an analogous manner.Translated from Izvestiya Vysshykh Uchebnykh Zavedenii, Fizika, No. 8, pp. 86–90, August, 1984.     

On the finite thermal conductivity of a one-dimensional rotator lattice

A heat transfer process is studied in a one-dimensional lattice of coupled rotators in which the orientation interaction between neighboring units is described by the periodic potential. Using this system as an example, it is demonstrated for the first time that one-dimensional lattices with a finite thermal conductivity in the thermodynamic limit can exist without substrate potential. As the temperature increases, the given system transforms from the state with an infinite thermal conductivity to the state with a finite thermal conductivity. The finiteness of the thermal conductivity stems from the existence of localized stationary excitations that interfere with heat transfer in the lattice. The lifetime and the concentration of these excitations increase with an increase in the temperature, which leads to a monotonic decrease in the thermal conductivity coefficient.     

Classical solitons with no quantum counterparts and their supersymmetric revival

We demonstrate the phenomenon stated in the title, using for illustration a two-dimensional scalar-field model with a triple-well potential {fx837-1}. At the classical level, this system supports static topological solitons with finite energy. Upon quantisation, however, these solitons develop infinite energy, which cannot be renormalised away. Thus this quantised model has no soliton sector, even though classical solitons exist. Finally when the model is extended supersymmetrically by adding a Majorana field, finiteness of the soliton energy is recovered.     

A note on infinities in eternal inflation

In some well-known scenarios of open-universe eternal inflation, developed by Vilenkin and co-workers, a large number of universes nucleate and thermalize within the eternally inflating mega-universe. According to the proposal, each universe nucleates at a point, and therefore the boundary of the nucleated universe is a space-like surface nearly coincident with the future light cone emanating from the point of nucleation, all points of which have the same proper-time. This leads the authors to conclude that at the proper-time t  =  t _nuc at which any such nucleation occurs, an infinite open universe comes into existence. We point out that this is due entirely to the supposition of the nucleation occurring at a single point, which in light of quantum cosmology seems difficult to support. Even an infinitesimal space-like length at the moment of nucleation gives a rather different result—the boundary of the nucleating universe evolves in proper time and becomes infinite only in an infinite time. The alleged infinity is never attained at any finite time.     

DOES THE RUBAKOV EFFECT EXIST IN AN SU(2) MODEL

In an SU(2) spontaneously broken gauge theory with a Higgs triplet, the mass effect of an iosspin 1/2 fermion on the fernlion-nlonopole bound states is discussed. It is shown that when the direct coupling betrveen fermion and Higgs field approaches zero, but the Dirac mass remalns finiteness, the necessary condition of the fermion-monopole bound state cannot be satisfied. This result means that the Rubakov effect is absent for SU(2) monopole because of the Dirac mass.     

Is There Paradox with Infinite Space?

We argue that an infinite universe should not necessarily be avoided on philosophical grounds. Paradoxes of repeating behaviour in the infinite, or eternal inflationary, universe can be alleviated by a realistic definition of differing lives: not simply permutations of various quantum states. The super-exponential growth in the rules of a cellular automata is used as an example of surpassing the holography bound. We also critically question the notion that our universe could simply be a simulation in somebody else's computer.     

Topology and the cosmic microwave background

Nature abhors an infinity. The limits of general relativity are often signaled by infinities: infinite curvature as in the center of a black hole, the infinite energy of the singular big bang. We might be inclined to add an infinite universe to the list of intolerable infinities. Many theories that move beyond general relativity naturally treat space as finite. In this review we discuss the mathematics of finite spaces and our aspirations to observe the finite extent of the universe in the cosmic background radiation.     

Topology and local-physical laws

In a closed universe, every physical system has a discrete infra-structure consisting of closely spaced (ΔE∼h ²/2mR²) energy eigen states. Basic physical principles such as the uncertainty relation as well as semi-empirical facts like the finiteness of the world age seem to exclude a detection of this structure.     

Topology of the Universe: Background and recent observational approaches

Is the Universe (a spatial section thereof) finite or infinite? Knowing the global geometry of a Friedmann-Lemaître (FL) universe requires knowing both its curvature and its topology. A flat or hyperbolic (‘open’) FL universe is not necessarily infinite in volume. Multiply connected flat and hyperbolic models are, in general, as consistent with present observations on scales of 1–20 h^?1 Gpc as are the corresponding simply connected flat and hyperbolic models. The methods of detecting multiply connected models (MCM’s) are presently in their pioneering phase of development and the optimal observationally realistic strategy is probably yet to be calculated. Constraints against MCM’s on ～1–4 h^?1 Gpc scales have been claimed, but relate more to inconsistent assumptions on perturbation statistics rather than just to topology. Candidate 3-manifolds based on hypothesised multiply imaged objects are being offered for observational refutation. The theoretical and observational sides of this rapidly developing subject have yet to make any serious contact, but the prospects of a significant detection in the coming decade may well propel the two together.