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Y. ihlo isl aegeteot orti h ether the retain to efforts great made himself Michelson and earth the were of motion years ether. repe- relative the succeeding any the detect the All to in unable ether. still experiment of their existence to of no appeared titions was result there mov- experimental that when the show velocity sun, experiment. its the in the altering around is always during ing earth is time earth the the the or all results Since ether frame These rest no ether is ether. the there and either earth existence that the the indicated of for motion evidence relative they experimental of apparatus, any and high-precision find earth the not the with did of Even motion pat- relative ether. fringe the the the tell in could of changes rotated. they motion was tern, the relative apparatus monitoring the the by when to ether Therefore, due the effect and would earth an pattern the fringe was The there pattern. if a fringe shift tele- at a a reflected traveled form entered were to and 2 beams scope recombined two and then O The mirrors, 1 point separate other. beams by at each These 2 to half-silvered and angle a too. 1 right at beams mirror source two degree the the into 45 by from split of light was angle of and an mirror beam at a experi- directed 1, their was FIG. In in Potsdam. shown in ment experiment repetition high-precision Michelson’s inter- a of Michelson is experiment the This called ferometer. now an high-precision is with ether Edward which a of interferometer, existence and out the carried Michelson demonstrate to Ohio Albert experiment important Cleveland, later, an in years give Morley to Six his as ether, accurate and result. so earth not the in is in of measurement experiment results motion of negitive relative the got motion the performed he detecting the He Although measuring Germany. it. by Potsdam, through ether earth of the existence test the experimental an for of possibility the the realised to Michelson, presence its reveal to refused ver- ether to pursuers. the dedicated were it, 1885-1905 ifying during ingenious many devoid papers Although was physics matter. and with was interaction space, any which of all medium pervaded ether frictionless, electromagnetic in an entirely of travel to presumed propagation to physicists medium the have For wave, waves a medium. sound needs air example, propagation the For wave it. that support us tells ics u te idhr.Mn hscssincluding physicists Many hard. died ether But Albert physicist, American 28-year-old a 1881, In ∗ if olwn ntegatsfootsteps, giant’s the in Following rief. e fslrsse r lopresented. also are system solar of del iesm xmlsi illustration in examples some give e rn hoyi t al er of years early its in theory tring umrz h rcs fthe of process the summarize —the 2

Mirror where we assume coordinate system Σ moves relative to another one Σ′ in the x-axes with uniform velocity v and γ = 1 [5]. Although he laid the foundation for 1− v2 Beam 1 c2 q Mirror the theory of relativity with his mathematical equations, Lorentz still tried to fit these remarkable equations into the ether hypothesis and save the ether from the contra- Light O 45˚ diction of the Michelson experiment. source All these efforts failed to explain the Michelson exper- Half-silvered Beam 2 iment while retaining the ether. It was genius Albert mirror Einstein who abandoned the ether entirely. He wrote in his celebrated paper on relativity in 1905[6]: “The introduction of a ‘light ether’ will prove to be 1 2 superfluous, inasmuch as in accordance with the concept to be developed here, no ‘space at absolute rest’ endowed with special properties will be introduced, nor will a ve- Telescope locity vector be assigned to a point of empty space at which electromagnetic processes are taking place.” Furthermore he developed the Special Relativity by conjucturing two postulations: FIG. 1: Diagram of Michelson-Morley experiment. A beam 1. The laws of nature are the same in all coordinate from a source was split into beams 1 and 2 at point O by a half-silvered mirror. The two beams were reflected by sep- systems moving with uniform motion relative to one an- arate mirrors and then entered a telescope to form a fringe other. pattern. 2. The speed of light is independent of the motion of its source. Of which, the first one is a natural generalization for yet explain the Michelson experiment. He attributed the all kinds of physical experience since it is reasonable to negative results to the earth dragging some of the ether expect that the laws of nature are the same with respect along with its motion. As a consequence the ether was to different inertial frames of reference. Whereas the sec- motionless with respect to the earth near its surface. ond one just represents a simple experimental fact. In George FitzGerald put forward another possible expla- Michelson’s experiment, the speed of light was found to nation in 1892 following the Lorentz-FitzGerald contrac- be constant with respect to the earth. Put in other words, tion equation, as we now know, the speed of light is the same for observers in different in- ertial frames of reference since an observer on the earth at two different times may be regarded as an observer v2 in two different inertial frames of reference. It is only a L = L0 1 − (1.2) r c2 small jump to the postulate of Einstein’s Special Relativ- ity that the speed of light is independent of the motion where L0 is called the proper length of an object which of its source. is measured in the rest frame of the object. To a mov- From the above condensed outline of the establishment ing observer of velocity v, any length along the direction of special relativity, we learn that when proposing an of motion undergoes a length contraction by a factor of idea or theory with which we may account for some un- − v2 explained phenomena, they should be based upon the 1 c2 . He proposed that the experimental appara- qtus would shorten in the direction parallel to the motion given facts of experiment or phenomena. Sometimes, the through the ether. This shrinkage would compensate the ideas may contradict well-known theories which are not light paths and prevent a displacement of the fringes due experimentally proved, such as the ether. If the prob- to the relative motion of the earth and the ether. lem is subtle and complicated, especially in physics, we Hendrik Lorentz discovered the well-known Lorentz should make incisive analyses, see through the general transformation in 1904 under which the electromagnetic appearance and grasp the underlying nature. The above theory expressed by the celebrated Maxwell equations method is of practical use in research which could be seen were in form invariant in all inertial frames. from the following four examples.

′ v t = γ(t − x) (1.3) II. FOUR EXAMPLES c2 ′ x = γ(x − vt) (1.4) ′ A good example in illustration of the method is the y = y (1.5) origin of quantum physics which now plays an important ′ z = z (1.6) role in various scientific areas. At the end of the nine- 3 teenth century, classical physics achieved great success. Another example concerns the situation of string the- But some experimental results were incompatible with ory in its early stage. We know that quantum field theory the classical physics such as the specific heat of a solid, worked well in the unification of quantum mechanics and the photoelectric effect and the thermal radiation of a electromagnetism in the 1940s. That it could also de- black body. Kirchhoff initiated his theoretical research scribe the weak and strong interactions was understood on thermal radiation in the 1850s. By the end of the by the end of 1960s. It has played a significant role in nineteenth century two important empirical formulae on our understanding of particle physics in many ways, from black-body radiation had been derived based upon the the formulation of the four-fermion interaction theory to fundamental thermodynamics. Wien proposed a formula the unification of electromagnetic and weak interactions for the energy density inside a black body in 1896, [9][10][11]. But when we attempted to incorporate it with gravity at high energy scale, severe problems appeared. c ν 3 2 For example, when E>Mp, the interaction of gravita- ρ(ν,T )= c1ν e T (2.1) tion can not be negligible, where where T is the temperature of the wall of a black body, ~c ν c1 c2 1/2 2 19 is the radiation frequency and , are two constants. Mp = ( ) c ≈ 1.2 × 10 Gev (2.4) Rayleigh and Jeans derived a result from a different ap- G proach in 1990, is Planck energy. The short-distance divergence problem of quantum gravity arouse. It was non-renormalizable 8πν2 even though we have employed the usual renormaliza- ρ(ν,T )= kT (2.2) c3 tion extracting the meaningful physical terms from the where k is the Boltzmann’s constant. The Rayleigh-Jeans divergences. formula was in agreement with the experimental curve String theory solved this severe problem. According at low frequencies whereas the Wien formula fitted the to the postulates in string theory, all elementary parti- experimental curve well at high frequencies. It was a cles, as well as the graviton were regarded as one dimen- great discrepancy at the turn of twentieth century that sional strings rather than point-like particles which were they failed to completely explain black-body radiation. generally accepted at the time. But the generally ac- Seemingly there was no way out since these formulae were cepted point-like particle concept was not experimentally based upon the fundamentals of classical physics. proved. Each string has a lot of different harmonics and Things changed on Dec. 14, 1900 when at a German the different elementary particles were regarded as differ- Physical Society meeting Max Planck presented his pa- ent harmonics in string theory. Therefore the world-line per entitled “On the theory of energy distribution law of a particle in quantum field theory shown in FIG. 2 was of normal spectrum” which not only solved the puzzel of replaced by its analog in string theory, the world-sheet black-body radiation but uncovered the quantum world. of a string which could join the world-sheet of another It marks the birth of quantum physics. He assumed that string smoothly. As a consequence, the vertex of an in- this energy could take on only a certain discrete set of teraction in a Feynman diagram was smeared out. In values such as 0, hν, 2hν, 3hν,..., where h is now known as string theory the massless spin two particle in the string Planck’s constant. These values are equally spaced rather spectrum was just right identified as the graviton which than being continuous. This assumption apparently con- mediates gravitation. At low energy scale the interac- tradicted the equipartition law and common sense. He tion of massless spin two particle is the same as that argued that the wall of a black body emitted radiation in required by general relativity. From this simple string the form of quanta with energy of integer mutiple of hν. postulate, string theory leads to a number of fruitful re- Based on this bold assumption[7], Planck gave a formula sults. It is the only currently known consistent theory of the energy density at frequency ν, of quantum gravity which does not have the above di- vergence problem. One of the vibrational forms of the 2 string possesses just the right property—spin two—to be 8πν hν a graviton whose couplings at long distance are those of ρ(ν,T )= 3 hν (2.3) c e kT − 1 general relativity. It admits chiral gauge couplings which which were in complete agreement with experimental have been the great difficulty for other unifying mod- results on general grounds. His formula was an inge- els. In addition, string theory predicts supersymmetry nious interpolation between the Wien formula and the and generates Yang-mills gauge fields and it has found Rayleigh-Jeans formula. We now know that it gives the many applications to mathematics in the area of topology correct explanation of the black body radiation spectrum. and geometry. Also in string theory there are no dimen- This proposal established his status in science. As Ein- tionless adjustable parameters which generally appear in quantum field theory, such as the fine-structure constant stein said[8]: 2 e “Very few will remain in the shrine of science, if we 4πǫ0~c . Nowadays, string theory (Detailed descriptions eliminate those moved by ambition, calculation, of what- may be found in Refs.[12]) has already become one of ever personal motivations; one of them will be Max the most active areas of research in physics. Thanks to Planck.” the postulate of one dimensional string. It sheds light 4 on and promises new insights to some deepest unsolved neutrino was experimentally detected by Fred Reines and problems in physics, for example, what cause the cosmic Clyde Cowan, at the Los Alamos lab in 1956[15] using a inflation? How does time begin? What constitutes the liquid scintillation device. This important discovery won dark matter and what is the so-called dark energy? the 1995 Nobel prize in physics. A lot of famous phe- The third example is upon the process of the discovery nomena and problems solved and unsolved, related with of the neutrino.(In this paper, all neutrino mean νe only.) the neutrino were found. Parity violation takes place In 1896, radioactivity was discovered by Henri Becquerel whenever there is the neutrino taking part in a weak in- which marked the birth of modern nuclear physics. Sub- teraction. This is just as the behavior of monopole under sequently three types of radioactive rays were identified. parity. They may be the same particle we think drawing They were called alpha ray, beta ray and gamma ray sep- inspiration from Einstein. So it causes the above viola- arately. Becquerel established that the beta rays were tion. Time reversal violation of this kind of weak interac- high-speed electrons in 1990. Employing electric and tion also is due to sign change of charges. When detecting magnetic fields, he deflected beta rays and found that neutrino emitted from the sun, fewer solar neutrino cap- they were negatively charged and that the ratio of charge ture rate than the predicted capture rate in chlorine from to mass of the beta particle was the same as that of an detailed models of the solar interior was found in 1968. electron. After more accurate measurements on beta de- This is the solar neutrino puzzel. We explain the flavor cays physicists found a serious problem. Unlike alpha change easily by the new nature of neutrino in solar neu- decay and gamma decay in which the emitted particles trino puzzel. In short, the change is by pair creation and carried away the well-defined energy which is equal to annihilation. Later the same phenomena were also ob- the total energy difference of the initial and final states, served by other groups using different materials. As the beta decay emited electrons with a continuous energy most fascinating particle, the neutrino is so important spectrum. It meant that a particular nucleus emitted that neutrino physics has become one of the most signif- an electron bearing unpredictable energy in a particular icant branches of modern physics. Thanks to the con- transition. This experimental result apparently violated jecture of the neutrino by Pauli. Although his proposal the conservation laws of energy and momentum. Wolf- contradicted the well-accepted knowledge at the time on gang Pauli proposed an entirely new particle-neutrino in beta decay process, his new beta decay process involving order to solve this serious problem. In his open letter[13] the neutrino was not completely impossible experimen- to the group of radioactives at the meeting of the regional tally. With this proposal we could overcome the serious society in Tubingen on December 4, 1930, he proposed problem and rescue the fundamental conservation laws the neutrino based on the given fact of experiment: of energy and momentum. The little neutrino has found “...This is the possibility that there might exist in the its application to a number of different research areas nuclei electrically neutral particles, which I shall call neu- in physics, such as in particle physics, nuclear physics, trons, which have spin 1/2, obey the exclusion principle cosmology and astrophysics. and moreover differ from light quanta in not travelling with the velocity of light.” “... I admit that my remedy may perhaps appear un- likely from the start, since one probably would long ago have seen the neutrons if they existed. But ‘nothing ven- ture, nothing win’, and the gravity of the situation with regard to the continuous beta spectrum is illuminated by Time a pronouncement of my respected predecessor in office, Herr Debye, who recently said to me in Brussels ‘Oh, it’s best not to think about it at all-like the new taxes’. One ought to discuss seriously every avenue of rescue.” In his letter, Pauli called his new proposed particle- Space the ”neutron” which is now called neutrino due to Enrico Fermi. Pauli proposed that this new speculative neutral particle might resolve the nonconservation of energy. If FIG. 2: A point particle’s world-line (left) in spacetime and the proposed neutrino and the electron were emitted si- its analog in string theory, world-sheet, traced out by a closed multaneously, the continuous spectum of energy might string (right) in spacetime. be explained by the sharing of energy and momentum of emitted particles in beta decay. It is worth mention- Finally we give an example of astronomy to show the ing that long before the neutrino was experimentally de- usefulness of our method deduced from the establishment tected, Enrico Fermi[14] incorporated Pauli’s proposal in of special relativity. Before the sixteenth century, it was his brilliant model for beta decay in the framework of extensively accepted that the sun, the moon and planets quantum electrodynamics in 1934. He showed clearly all orbited about the earth which was at the center of with his beta decay theory that the neutron decayed into the universe. In his famous book, Almagest, the antient a proton, an electron and a neutrino simultaneously. The Greek astronomer Claudius Ptolemy proposed the earth- 5 centered model of the universe. He proved that the earth ing motions of the planets in a simple way using his new was round and the gravity everywhere pointed to the cen- helio-centric model. They were the direct consequence ter of the earth. Every planet moved along an epicycle of the relative motion of the planets and the earth when whose center revolved around the earth just as the sun people saw from the earth. and the moon revolving around the earth. The epicycle He could not prove his radical helio-centric model at was carried along on a larger circle like a frisbee spin- the time. Although he simplified the cumbersome Ptole- ning on the rim of a rotating wheel shown in FIG. 3. maic system, both the earth-centered model and the He postulated the epicycle to explain the looping mo- helio-centric model could account for the observations tion of a planet. The people on the earth would not see of motion of the celestial bodies. Copernicus’s theory the observed irregular motion of a planet if the planet gives an alternative theory of Ptolemy. Even though the moved around the earth in a circular orbit, rather than problem was subtle and complicated, we should grasped in a epicycle. The Ptolemaic model of the universe was the hidden nature behind the phenomena. As Coper- the obvious and direct inference when people observed nicus pointed out that the extremely massive sun must the motion of the sun day after day and the motions of rule over the much smaller planet and the earth. He the moon and the planets night after night. Therefore therefore drew his conclusion that it was the earth that Ptolemy’s theory was well-accepted and prevailed for a moved around rather than the sun. It was Isaac Newton long time. who provided the correct explanation of Kepler’s laws and convinced people that the earth and other planets revolved around the massive sun due to the attractive force with his ingenious universal law of gravitation[17]. Center of Mm epicycle Planet F = G (2.5) r2

where F is the universal gravitation force between the two bodies with mass M and m respectively, G is called Epicycle the gravitational constant, and r is the distance between the centers of mass of the two bodies. Galileo Galilei first observed the four satellites orbited around Jupiter which exhibited undoubtedly that the earth were not the center Earth of all circular motions of the celestial bodies utilizing his telescopes. He stated the four small bodies moved around the larger planet-Jupiter like Venus and Mercury around the sun. Also he observed the phases of Venus which was the direct result of the planet moving around the sun.

III. SUMMARY AND CONCLUSION FIG. 3: An illustration of the Ptolemaic model.

In about 1510, Nicholas Copernicus presented the We have reviewed the process of the establishment helio-centric model. In his celebrated book published of Special Relativity against the background of physics in 1543, De Revolutionibus orbium coelestium, he pos- around the turn of the twentieth century in our paper. tulated that the planets including the earth all moved Moreover we have outlined the scientific method which around the sun shown in FIG. 4[16]. (In 1781, William helps to do research. Some examples are presented in and Caroline Herschel discovered Uranus, the first planet order to illustrate the usefulness of the method. We have found beyond the Saturn boundary, which was generally discussed the origin of quantum physics and string the- acknowledged as the outer limit of the solar system for ory in its early years of development. Discoveries of the thousands of years. Neptune was discovered in 1846 by neutrino and the correct model of solar system have also Johann Galle. The discovery of Neptune was a great been demonstrated. We have shown that the method is of triumph for theoretical astronomy since Neptune was at practical use in a wide range, from physics to astronomy, first predicted by Adams and Le Verrier using mathe- from ancient science to modern ones. This year is the un- matical arguments based on Newton’s universal gravi- precedented World Year of Physics which acknowledges tation law and then observed near their predicted loca- the contribution of physics to the world. It marks the tions. Pluto was predicted by Percival Lowell and found hundredth anniversary of the pioneering contributions of in 1930 by Clyde Tombaugh.) The earth spin about its Albert Einstein in 1905 as well as the fiftieth anniversary axis one rotation per day and revolved around the sun in of his death in 1955. We dedicate this paper to Albert the plane of the ecliptic. He explained the apparent loop- Einstein. 6

Saturn

Mercury

Earth Sun Venus Mars

Jupiter

FIG. 4: An illustration of the Copernican model in which the planets, including the earth, all orbited around the sun. His heliocentric concept contradicted Ptolemy’s model, the well-accepted model treated with respected at the time.

[1] A. Einstein, Annalen der Physik 17, 891 (1905) 8th Nobel symposium, Aspenasgarden, 1968, ed. by N. [2] A. Einstein, Annalen der Physik 17, 132 (1905) Svartholm, p.367 [3] A. Einstein, Annalen der Physik 17, 549 (1905) [12] M. B. Green, J. H. Schwarz and E. Witten, Superstring [4] A. Einstein, Annalen der Physik 17, 639 (1905) theory, Vols. 1 and 2, Cambridge University Press, Cam- [5] J. D. Jackson, Classical Electrodynamics, 2nd edition, bridge, UK(1987) John Wiley & Sons, New York, (1975) [13] Charles Enz, No time to be brief-A scientific biography [6] A. Beck and P. Havas, The collected papers of Albert Ein- of Wolfgang Pauli, Oxford university press, (2002) stein, English translation 2, Princeton University Press, [14] E. Fermi, Z. fur Physik 88,161, (1934) Princeton, USA(1987) [15] F. Reines and C. Cowan, Science, 124 (1956) 10 [7] Max Planck, Annalen der physik, 4, 553 (1901) [16] J. Adamczewski, Nicolaus Copernicus and his Epoch, [8] Max Planck, Where is science going? (Several essays by Copernicus Society of Americ Max Planck. Prologue by Albert Einstein), Dover, New [17] Isaac Newton, Mathematical Principles of Natural Phi- York (1981) losophy and His System of the World, Univ. of Calif. [9] S. L. Glashow, Nucl. Phys. 22, 579 (1961). Press, Berkeley, CA (1962) [10] S. Weinberg, Phys. Rev. Lett. 19, 1264 (1967). [11] A. Salam, in Elementary Particle Theory, Proc. of the