PERIOD 1900-1945The decisive events

PERIOD 1900-1945
The decisive events of the first period have been the conception of the Theory of Relativity and that of Quantum Mechanics. Rarely in the history of science have two complexes of ideas so fundamentally influ-enced natural science in general.
There are important differences between the two achievements. Rel¬ativity theory should be regarded as the crowning of classical physics of the eighteenth and nineteenth centuries. The special theory of relativity brought about a unification of mechanics and electromagnetism. These two fields were inconsistent with each other, when dealing with fast-moving electrically charged objects. Of course, relativity created new notions, such as the relativity of simultaneity, the famous mass-energy relation, the idea that gravity can be described as a curvature of space. But, altogether, the theory of relativity uses the concepts of classical phys-ics, such as position, velocity, energy, momentum, etc. Therefore it must be regarded as a conservative theory, establishing a logically coherent system within the edifice of classical physics.
Quantum mechanics was truly revolutionary. It is based on the recog¬nition that the classical concepts do not fit the atomic and molecular world: a new way to deal with that world was created. Limits were set to the applicability of classical concepts by Heisenberg's uncertainty relations. They say 'down to here and no further can you apply classical concepts'. This is why it would have been better to call them 'Limiting Relations'. It would also have been advantageous to call relativity theory 'Absolute Theory', since it describes the laws of Nature independently of the systems of reference. Much philosophical abuse would have been avoided.
It took a quarter of a century to develop non-relativistic Quantum Mechanics. Once conceived, an explosive development occurred. With¬in a few years most atomic and molecular phenomena could be under-stood, at least in principle. It is appropriate to quote a slightly altered version of a statement by Churchill praising the Royal Air Force: 'Never have so few done so much in so short a time'.
A few years later, the combination of relativity and quantum me¬chanics yielded new unexpected results. P.A.M. Dirac conceived his relativistic wave equation which contained the electron spin and the fine structure of spectral lines as a natural consequence. The application of quantum mechanics to the electromagnetic field gave rise to Quantum Electrodynamics with quite a number of surprising consequences, some of them positive, others negative.
The positive ones included Dirac's prediction of the existence of an antiparticle to the electron, the positron, which was found afterwards in 1932 by CD. Anderson and S.H. Nedermeyer. Most surprising were the predictions of the creation of particle- antiparticle pairs by radiation or other forms of energy and the annihilation of such pairs with the emis¬sion of light or other energy carriers. Another prediction was the exist-ence of an electric polarization of the vacuum in strong fields. All these new processes were found experimentally later on.
The negative ones are consequences of the infinite number of degrees of freedom in the radiation field. Infinities appeared in the coupling of an electron with its field and in the vacuum polarization when the contri¬bution of high-frequency fields is included. These infinities cast a shad¬ow on quantum electrodynamics until 1946 when a way out was found by the so-called renomalization method.
Parallel to the events in physics during Period I, chemistry, biology, and geology also developed at a rapid pace. The quantum mechanical explanation of the chemical bond gave rise to quantum chemistry that allowed a much deeper understanding of the structure and properties of molecules and of chemical reactions. Biochemistry became a growing branch of chemistry. Genetics was established as a branch of biology, recognizing the chromosomes as carriers of genes, the elements of inher¬itance. Proteins were identified as essential components of living sys¬tems. The knowledge of enzymes, hormones, and vitamins vastly in¬creased during that period. Embryology began to investigate the early development of living systems: how the cellular environment regulates the genetic program. Darwin's idea of evolution was considered in greater detail, recognizing the lack of inheritance of acquired properties. A kind of revolution was also started in geology by A. Wegener's concept of plate tectonics and continental drift. W. Elsasser's suggestion of eddy currents in the liquid-iron core of the Earth as the source of the Earth's magnetism was published at the end of Period I, and led to the solution of a hitherto unexplained phenomenon.
The year 1932 was a miracle year in physics. The neutron was dis¬covered by J. Chadwick, the positron was found by Anderson and Nedermeyer, a theory of radioactive decay was formulated by E. Fermi in anal

Результаты (русский) 1:

ПЕРИОД 1900-1945 ГГ.Решительные события первого периода были концепция теории относительности и что квантовой механики. Редко в истории науки есть два комплекса идей настолько основно Рован enced естественные науки в целом.Существуют важные различия между двумя достижениями. Rel¬ativity теория следует рассматривать как коронование классической физики XVIII и XIX веках. Специальная теория относительности привело объединения механики и электромагнетизм. Эти два поля несовместимы друг с другом, при работе с быстро движущихся электрически заряженных объектов. Конечно теория относительности создал новые понятия, такие как относительность одновременности, известные отношения массы энергии, идея, что гравитация можно охарактеризовать как кривизны пространства. Но, в целом теория относительности использует концепции классического РЬуз ics, например, положение, скорость, энергия, импульс и др. Поэтому он должен рассматриваться как консервативной теории, создания логически целостной системы в здании классической физики. Квантовая механика была поистине революционным. Он основан на recog¬nition, что классические концепции не соответствуют атомном и молекулярном мире: был создан новый способ борьбы с этого мира. Ограничения были установлены для применимости классической концепции отношений неопределенности Гейзенберга. Они говорят, «вниз здесь и не далее можно применять классические концепции». Именно поэтому было бы лучше назвать их «Ограничение отношений». Также было бы выгодно для вызова теории относительности «Абсолютной теории», так как он описывает законы природы, независимо от систем ведения. Много философски злоупотребление было бы избежать.Он взял четверть века для разработки non релятивистской квантовой механики. После того, как задумано, произошло взрывное развитие. With¬in несколько лет наиболее атомных и молекулярных явлений могут быть под стоял, по крайней мере в принципе. Это уместно процитировать слегка измененную версию заявления Черчилля, хваля королевских ВВС: «Никогда не так мало сделал так много в столь короткое время».Несколько лет спустя, сочетание теории относительности и квантовой me¬chanics принесли новые неожиданные результаты. Абстрагироваться. Дирак зачала его релятивистское волновое уравнение, который содержит спин электрона и тонкой структуры спектральных линий как естественное следствие. Применение квантовой механики к электромагнитному полю привело к квантовой электродинамики с целый ряд удивительно последствий, некоторые из них положительные, другие отрицательные.The positive ones included Dirac's prediction of the existence of an antiparticle to the electron, the positron, which was found afterwards in 1932 by CD. Anderson and S.H. Nedermeyer. Most surprising were the predictions of the creation of particle- antiparticle pairs by radiation or other forms of energy and the annihilation of such pairs with the emis¬sion of light or other energy carriers. Another prediction was the exist-ence of an electric polarization of the vacuum in strong fields. All these new processes were found experimentally later on.The negative ones are consequences of the infinite number of degrees of freedom in the radiation field. Infinities appeared in the coupling of an electron with its field and in the vacuum polarization when the contri¬bution of high-frequency fields is included. These infinities cast a shad¬ow on quantum electrodynamics until 1946 when a way out was found by the so-called renomalization method.Parallel to the events in physics during Period I, chemistry, biology, and geology also developed at a rapid pace. The quantum mechanical explanation of the chemical bond gave rise to quantum chemistry that allowed a much deeper understanding of the structure and properties of molecules and of chemical reactions. Biochemistry became a growing branch of chemistry. Genetics was established as a branch of biology, recognizing the chromosomes as carriers of genes, the elements of inher¬itance. Proteins were identified as essential components of living sys¬tems. The knowledge of enzymes, hormones, and vitamins vastly in¬creased during that period. Embryology began to investigate the early development of living systems: how the cellular environment regulates the genetic program. Darwin's idea of evolution was considered in greater detail, recognizing the lack of inheritance of acquired properties. A kind of revolution was also started in geology by A. Wegener's concept of plate tectonics and continental drift. W. Elsasser's suggestion of eddy currents in the liquid-iron core of the Earth as the source of the Earth's magnetism was published at the end of Period I, and led to the solution of a hitherto unexplained phenomenon.The year 1932 was a miracle year in physics. The neutron was dis¬covered by J. Chadwick, the positron was found by Anderson and Nedermeyer, a theory of radioactive decay was formulated by E. Fermi in anal