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THE NATURE : EVOLUTION OF PHILOSOPHY AND PHYSICS.
PROLOGUE :
As human being discovered a technique to have a fire, by rubbing two stones together, they had started to apply the fire to the other fields like cooking, as they learned cooking, next they started to look forward for a strong shelter, and they got caves to live in. The next phase of evolution was fast and quickly human being learned to cultivate. Once they developed the process of cultivation, it spelts a great relief to human being, as it gave them the much needed food security. It translated into leisure time for some of them due to food security, caves already gave them life security from the predators. Getting time to think was a revolutionary moments for the entire human race as the signs of language, and intelligence had bloomed thereafter. After bipedalism, cultivation is one of the turning points of the entire human races across the globe.
During these periods the change in the food patterns accelerated the evolution of human brain up to a threshold, when it became self aware as it successfully developed the processes responsible for human thinking.
The greatest evolutionary trait on this world is the development of thinking mind inside the human brain. Nobody is sure whether mind or body is the same thing or they are related by some complex process.
THE ANCIENT PHILOSOPHERS :
From 3500 BC to 350 BC, the time period is called as BRONZE AGE, as by that time human being already learned to extract metals and make alloy out of their mixture. Bronze is such an alloy used in the human society at that era. It is universally assumed that the first civilizations grew up in The MIDDLE EAST. Next, came IRON AGE when human being learned the use of Iron, in this era, The Persians, Egyptians, Greeks and Romans spread this culture through conquests and trade. On the other hand Chinese and Indians were observing the heavens and starting their own culture as well as science too.
ANCIENT SUMERIA : THE FLOURISH OF CITY-BUILDING TECHNOLOGY AND ARITHMETIC :
Sumerians lived in Mesopotamia, now modern day Iraq. The region was bounded the rivers Tigris and Euphrates. They were one of the most advanced civilisations of that time. They were the first advanced civilisations who built cities to live in with proper administrations, legal systems as well as irrigation too. The importantly they first developed methods of writing and counting in base 60.
EARLIEST TIMES - 1550 AD:
The Greeks gave much to the world of physics by developing the basis of fundamental modern principles as the conservation of matter, atomic theory, and the like. Very few new developments occurred in the centuries following the Greek period. However, as the intense intellectual force of the Renaissance entered the field of physics, Copernicus and other great thinkers began to reject the Greek ideas in favor of new ideas based on empirical methods. Since Copernicus' theories ended the old era of scientific understanding as much as began the new scientific revolution, it is fitting to include him with the ancient thinkers.
624-547 B.C.
Thales of Miletus postulates that water is the basic substance of the Earth. He also was acquainted with the attractive power of magnets and rubbed amber.
580-500 B.C.
Pythagoras held that the Earth was spherical. He sought a mathematical understanding of the universe.
Anaxagoras and Empedocles.
Anaxagoras (500-428 B.C.) challenged the previous Greek contention about the creation and destruction of matter by teaching that changes in matter are due to different orderings of indivisible particles (thus his teachings were a precursor to the law of the conservation of matter).
Empedocles (484-424 B.C.) reduced these indivisible partices into four elements: earth, air, fire, and water.
460 - 370 B.C.
Democritus developed the theory that the universe consists of empty space and an (almost) infinite number of invisible particles which differ from each other in form, position, and arrangement. All matter is made of indivisible particles called atoms.
384-322 B.C.
Aristotle formalized the gathering of scientific knowledge. While it is difficult to point to one particular theory, the total result of his compilation of knowledge was to provide the fundamental basis of science for a thousand years.
310-230 B.C.
Aristarchus describes a cosmology identical to that proposed by Copernicus 2,000 years later. However, given the great prestige of Aristotle, Aristarchus' heliocentric model was rejected in favor of the geocentric model.
287-212 B.C.
Archimedes was a great pioneer in theoretical physics. He provided the foundations of hydrostatics.
70-147 AD
Ptolemy of Alexandria collected the optical knowledge of the time. He also invented a complex theory of planetary motion.
~1000 AD
Alhazen, an Arab, produced 7 books on optics.
1214 - 1294 AD
Roger Bacon taught that in order to learn the secrets of nature we must first observe. He thus provided the method by which people can develop deductive theories using evidence from the natural world.
1473 - 1543 AD
Nicholaus Copernicus set forth the theory that the earth revolves around the sun. This heliocentric model was revolutionary in that it challenged the previous dogma of scientific authority of Aristotle, and caused a complete scientific and philosophical upheaval.
"Following the Copernican revolution, it was apparent that scientifc theories could not be accepted without rigorous testing. Communication among scientists increased and spurred more discoveries."
1564 - 1642
Galileo Galilei is considered by many to be the father of modern physics because of his willingness to replace old assumptions in favor of new scientifically deduced theories. He is famous for his celestial theories, and his works on mechanics paved the way for Newton.
1546 - 1601, 1571 - 1630
Tycho Brahe and Johannes Kepler. Brahe's accurate celestial data allow Kepler to develop his theory of elliptical planetary motion and provide evidence for the Copernican system. In addition, Kepler writes a qualitative description of gravitation.
1642 - 1727
Sir Isaac Newton develops the laws of mechanics (now called classical mechanics) which explains object motion in a mathematical fashion.
1773 - 1829
Thomas Young develops the wave theory of light and describes light interference.
1791 - 1867
Michael Faraday creates the electric motor, and develops an understanding of electromagnetic induction, which provides evidence that electricity and magnetism are related. In addition, he discovers electrolysis and describes the conservation of energy law.
1799 - 1878
Joesph Henry's research on electromagnetic induction is performed at the same time as Faraday's. He constructs the first motor; his work with electromagnets leads directly to the development of the telegraph.
1873
James Clerk Maxwell performs important research in three areas: color vision, molecular theory, and electromagnetic theory. The ideas underlying Maxwell's theories of electromagnetism describes the propagation of light waves in a vacuum.
1874
George Stoney develops a theory of the electron and estimates its mass.
1895
Wilhelm Röntgen discovers x rays.
1898
Marie and Pierre Curie separate radioactive elements.
1898
Joseph Thompson measures the electron, and puts forth his "plum-pudding" model of the atom -- that the atom is a slightly positive sphere with small, raisin-like negative electrons inside.
At the start of the twentieth century, scientists believed that they understood the most fundamental principles of nature. Atoms were solid building blocks of nature; people trusted Newtonian laws of motion; most of the problems of physics seemed to be solved. However, starting with Einstein's theory of relativity which replaced Newtonian mechanics, scientists gradually realized that their knowledge was far from complete. Of particular interest was the growing field of quantum mechanics, which completely altered the fundamental precepts of physics.
1900
Max Planck suggests that radiation is quantized (it comes in discrete amounts.)
1905
Albert Einstein, one of the few scientists to take Planck's ideas seriously, proposes a quantum of light (the photon) which behaves like a particle. Einstein's other theories explained the equivalence of mass and energy, the particle-wave duality of photons, the equivalence principle, and special relativity.
1909
Hans Geiger and Ernest Marsden, under the supervision of Ernest Rutherford, scatter alpha particles off a gold foil and observe large angles of scattering, suggesting that atoms have a small, dense, positively charged nucleus.
1911
Ernest Rutherford infers the nucleus as the result of the alpha-scattering experiment performed by Hans Geiger and Ernest Marsden.
1912
Albert Einstein explains the curvature of space-time.
1913
Niels Bohr succeeds in constructing a theory of atomic structure based on quantum ideas.
1919
Ernest Rutherford finds the first evidence for a proton.
1921
James Chadwick and E.S. Bieler conclude that some strong force holds the nucleus together.
1923
Arthur Compton discovers the quantum (particle) nature of x rays, thus confirming photons as particles.
1924
Louis de Broglie proposes that matter has wave properties.
1925 (Jan)
Wolfgang Pauli formulates the exclusion principle for electrons in an atom.
1925 (April)
Walther Bothe and Hans Geiger demonstrate that energy and mass are conserved in atomic processes.
1926
Erwin Schroedinger develops wave mechanics, which describes the behavior of quantum systems for bosons. Max Born gives a probability interpretation of quantum mechanics. G.N. Lewis proposes the name "photon" for a light quantum.
1927
Certain materials had been observed to emit electrons (beta decay). Since both the atom and the nucleus have discrete energy levels, it is hard to see how electrons produced in transition could have a continuous spectrum (see 1930 for an answer.)
1927
Werner Heisenberg formulates the uncertainty principle: the more you know about a particle's energy, the less you know about the time of the energy (and vice versa.) The same uncertainty applies to momenta and coordinates.
1928
Paul Dirac combines quantum mechanics and special relativity to describe the electron.
1930
Quantum mechanics and special relativity are well established. There are just three fundamental particles: protons, electrons, and photons. Max Born, after learning of the Dirac equation, said, "Physics as we know it will be over in six months."
1930
Wolfgang Pauli suggests the neutrino to explain the continuous electron spectrum for beta decay.
1931
Paul Dirac realizes that the positively-charged particles required by his equation are new objects (he calls them "positrons"). They are exactly like electrons, but positively charged. This is the first example of antiparticles.
1931
James Chadwick discovers the neutron. The mechanisms of nuclear binding and decay become primary problems.
1933-34
Enrico Fermi puts forth a theory of beta decay that introduces the weak interaction. This is the first theory to explicitly use neutrinos and particle flavor changes.
1933-34
Hideki Yukawa combines relativity and quantum theory to describe nuclear interactions by an exchange of new particles (mesons called "pions") between protons and neutrons. From the size of the nucleus, Yukawa concludes that the mass of the conjectured particles (mesons) is about 200 electron masses. This is the beginning of the meson theory of nuclear forces.
1937
A particle of 200 electron masses is discovered in cosmic rays. While at first physicists thought it was Yukawa's pion, it was later discovered to be a muon.
1938
E.C.G. Stückelberg observes that protons and neutrons do not decay into any combination of electrons, neutrinos, muons, or their antiparticles. The stability of the proton cannot be explained in terms of energy or charge conservation; he proposes that heavy particles are independently conserved.
1941
C. Moller and Abraham Pais introduce the term "nucleon" as a generic term for protons and neutrons.
1946-47
Physicists realize that the cosmic ray particle thought to be Yukawa's meson is instead a "muon," the first particle of the second generation of matter particles to be found. This discovery was completely unexpected -- I.I. Rabi comments "who ordered that?" The term "lepton" is introduced to describe objects that do not interact too strongly (electrons and muons are both leptons).
1947
A meson that does interact strongly is found in cosmic rays, and is determined to be the pion.
1947
Physicists develop procedures to calculate electromagnetic properties of electrons, positrons, and photons. Introduction of Feynman diagrams.
1948
The Berkeley synchro-cyclotron produces the first artificial pions.
1949
Enrico Fermi and C.N. Yang suggest that a pion is a composite structure of a nucleon and an anti-nucleon. This idea of composite particles is quite radical.
1949
Discovery of K+ via its decay.
1950
The neutral pion is discovered.
1951
Two new types of particles are discovered in cosmic rays. They are discovered by looking a V-like tracks and reconstructing the electrically-neutral object that must have decayed to produce the two charged objects that left the tracks. The particles were named the lambda0 and the K0.
1952
Discovery of particle called delta: there were four similar particles (delta++, delta+, delta0, and delta-.)
1952
Donald Glaser invents the bubble chamber. The Brookhaven Cosmotron, a 1.3 GeV accelerator, starts operation.
1953
The beginning of a "particle explosion" -- a true proliferation of particles.
1953 - 57
Scattering of electrons off nuclei reveals a charge density distribution inside protons, and even neutrons. Description of this electromagnetic structure of protons and neutrons suggests some kind of internal structure to these objects, though they are still regarded as fundamental particles.
1954
C.N. Yang and Robert Mills develop a new class of theories called "gauge theories." Although not realized at the time, this type of theory now forms the basis of the Standard Model.
1957
Julian Schwinger writes a paper proposing unification of weak and electromagnetic interactions.
1957-59
Julian Schwinger, Sidney Bludman, and Sheldon Glashow, in separate papers, suggest that all weak interactions are mediated by charged heavy bosons, later called W+ and W-. Actually, it was Yukawa who first discussed boson exchange twenty years earlier, but he proposed the pion as the mediator of the weak force.
1961
As the number of known particles keep increasing, a mathematical classification scheme to organize the particles (the group SU(3)) helps physicists recognize patterns of particle types.
1962
Experiments verify that there are two distinct types of neutrinos (electron and muon neutrinos). This was earlier inferred from theoretical considerations.
By the mid-1960's, physicists realized that their previous understanding, where all matter is composed of the fundamental protons, neutrons, and electron, was insufficient to explain the myriad new particles being discovered. Gell-Mann's and Zweig's quark theory solved these problems. Over the last thirty years, the theory that is now called the Standard Model of particles and interactions has gradually grown and gained increasing acceptance with new evidence from new particle accelerators.
1964
Murray Gell-Mann and George Zweig tentatively put forth the idea of quarks. They suggested that mesons and baryons are composites of three quarks or antiquarks, called up, down, or strange (u, d, s) with spin 0.5 and electric charges 2/3, -1/3, -1/3, respectively (it turns out that this theory is not completely accurate). Since the charges had never been observed, the introduction of quarks was treated more as a mathematical explanation of flavor patterns of particle masses than as a postulate of actual physical object. Later theoretical and experimental developments allow us to now regard the quarks as real physical objects, even though they cannot be isolated.
1964
Since leptons had a certain pattern, several papers suggested a fourth quark carrying another flavor to give a similar repeated pattern for the quarks, now seen as the generations of matter. Very few physicists took this suggestion seriously at the time. Sheldon Glashow and James Bjorken coin the term "charm" for the fourth (c) quark.
1965
O.W. Greenberg, M.Y. Han, and Yoichiro Nambu introduce the quark property of color charge. All observed hadrons are color neutral.
...1966...
The quark model is accepted rather slowly because quarks hadn't been observed.
1967
Steven Weinberg and Abdus Salam separately propose a theory that unifies electromagnetic and weak interactions into the electroweak interaction. Their theory requires the existence of a neutral, weakly interacting boson (now called the Z0) that mediates a weak interaction that had not been observed at that time. They also predict an additional massive boson called the Higgs Boson that has not yet been observed.
1968-69
At the Stanford Linear Accelerator, in an experiment in which electrons are scattered off protons, the electrons appear to be bouncing off small hard cores inside the proton. James Bjorken and Richard Feynman analyze this data in terms of a model of constituent particles inside the proton (they didn't use the name "quark" for the constituents, even though this experiment provided evidence for quarks.)
1970
Sheldon Glashow, John Iliopoulos, and Luciano Maiani recognize the critical importance of a fourth type of quark in the context of the Standard Model. A fourth quark allows a theory that has flavor-conserving Z0-mediated weak interactions but no flavor-changing ones.
1973
Donald Perkins, spurred by a prediction of the Standard Model, re-analyzes some old data from CERN and finds indications of weak interactions with no charge exchange (those due to a Z0 exchange.)
1973
A quantum field theory of strong interaction is formulated. This theory of quarks and gluons (now part of the Standard Model) is similar in structure to quantum electrodynamics (QED), but since strong interaction deals with color charge this theory is called quantum chromodynamics (QCD). Quarks are determined to be real particles, carrying a color charge. Gluons are massless quanta of the strong-interaction field. This strong interaction theory was first suggested by Harald Fritzsch and Murray Gell-Mann.
1973
David Politzer, David Gross, and Frank Wilczek discover that the color theory of the strong interaction has a special property, now called "asymptotic freedom." The property is necessary to describe the 1968-69 data on the substrate of the proton.
1974
In a summary talk for a conference, John Iliopoulos presents, for the first time in a single report, the view of physics now called the Standard Model. If you want to understand the various aspects of the Standard Model, please explore the Standard Model Path.
1974 (Nov.)
Burton Richter and Samuel Ting, leading independent experiments, announce on the same day that they discovered the same new particle. Ting and his collaborators at Brookhaven called this particle the "J" particle, whereas Richter and his collaborators at SLAC called this particle the psi particle. Since the discoveries are given equal weight, the particle is commonly known as the J/psi particle. The J/psi particle is a charm-anticharm meson.
1976
Gerson Goldhaber and Francois Pierre find the D0 meson (anti-up and charm quarks). The theoretical predictions agreed dramatically with the experimental results, offering support for the Standard Model.
1976
The tau lepton is discovered by Martin Perl and collaborators at SLAC. Since this lepton is the first recorded particle of the third generation, it is completely unexpected.
1977
Leon Lederman and his collaborators at Fermilab discover yet another quark (and its antiquark). This quark was called the "bottom" quark. Since physicists figured that quarks came in pairs, this discovery adds impetus to search for the sixth quark -- "top."
1978
Charles Prescott and Richard Taylor observe a Z0 mediated weak interaction in the scattering of polarized electrons from deuterium which shows a violation of parity conservation, as predicted by the Standard Model, confirming the theory's prediction.
1979
Strong evidence for a gluon radiated by the initial quark or antiquark if found at PETRA, a colliding beam facility at the DESY laboratory in Hamburg,
1983
The W± and Z0 intermediate bosons demanded by the electroweak theory are observed by two experiments using the CERN synchrotron using techniques developed by Carlo Rubbia and Simon Van der Meer to collide protons and antiprotons.
1989
Experiments carried out in SLAC and CERN strongly suggest that there are three and only three generations of fundamental particles. This is inferred by showing that the Z0-boson lifetime is consistent only with the existence of exactly three very light (or massless) neutrinos.
1995
After eighteen years of searching at many accelerators, the CDF and D0 experiments at Fermilab discover the top quark at the unexpected mass of 175 GeV. No one understands why the mass is so different from the other five quarks.
