World Year of Physics 2005
Encyclopedia
The year 2005 has been named the World Year of Physics in recognition of the 100th anniversary of Albert Einstein's
"Miracle Year
," in which he published four landmark papers, and the subsequent advances in the field of physics
.
has been the basis for understanding the physical world and nature as a whole. The applications of physics are the basis for much of today's technology. In order to both raise the worldwide awareness of physics and celebrate the major advances made in the field, the International Union of Pure and Applied Physics resolved that 2005 should be commemorated as the World Year of Physics. This has subsequently been endorsed by both the United Nations
and the United States Congress
http://www.theithacajournal.com/news/stories/20050514/localnews/2136011.html.
, introduced the special theory of relativity, and described how the photoelectric effect
could be explained by the quantization
of light, which helped launch quantum mechanics
, and developed E = mc2. These papers are commonly called his Annus Mirabilis Papers
because they later defined 1905 as a miracle year for physics.
Most physicists agree that the first three of those papers deserved Nobel Prize
s, but only the paper on the photoelectric effect would win one. What makes these papers remarkable is that, in each case, Einstein boldly took an idea from theoretical physics to its logical consequences and managed to explain experimental results that had baffled scientists for decades.
" and showed how it could be used to explain such phenomena as the photoelectric effect
. The idea of energy quanta was motivated by Max Planck
's earlier derivation of the law of black-body radiation by assuming that luminous energy
could only be absorbed or emitted in discrete amounts, called quanta. Einstein showed that, by assuming that light
actually consisted of discrete packets, he could explain the mysterious photoelectric effect.
The idea of light quanta contradicted the wave theory of light that followed naturally from James Clerk Maxwell
's equations for electromagnetic
behavior and, more generally, the assumption of infinite divisibility
of energy in physical systems. Even after experiments showed that Einstein's equations for the photoelectric effect were accurate, his explanation was not universally accepted. However, by 1921, when he was awarded the Nobel Prize and his work on photoelectricity was mentioned by name in the award citation, most physicists thought that light quanta were possible. A complete picture of the photoelectric effect was only obtained after the maturity of quantum mechanics.
model of Brownian motion
. Brownian motion generates expressions for the root mean square
displacement
of particles. Using the then-controversial kinetic theory of fluids, it established that the phenomenon, which still lacked a satisfactory explanation decades after it was first observed, provided empirical evidence for the reality of atom
s. It also lent credence to statistical mechanics
, which was also controversial at the time.
Before this paper, atoms were recognized as a useful concept, but physicists and chemists hotly debated whether atoms were real entities. Einstein's statistical discussion of atomic behavior gave experimentalists a way to count atoms by looking through an ordinary microscope. Wilhelm Ostwald
, one of the leaders of the anti-atom school, later told Arnold Sommerfeld
that he had been converted to a belief in atoms by Einstein's complete explanation of Brownian motion.
, but omitted the force of gravity.
Special relativity avoids the problem in science that was present after the Michelson-Morley experiment
failed to measure a speed difference between perpendicular light beams, by postulating that the speed of light
is not relative to some medium and is the same for all observers irrespective of their relative velocities. This is unlike all other known wave
s, which require a medium (such as water
or air) to propagate.
Einstein's explanation arises from two postulates: The first is Galileo
's idea that the laws of nature are the same for all observers that move with constant velocity relative to each other. The second was that the speed of light
is the same for every observer.
Special relativity has several striking consequences, because the concepts of absolute time and space
are incompatible with an absolute speed of light. The theory abounds with paradox
es and appeared to make little sense, landing Einstein substantial ridicule, but he eventually managed to work out the apparent contradictions and solve the problems.
's calculus
. Although his 1905 paper on the photoelectric effect helped spur the development of quantum mechanics, Einstein himself considered quantum theory, which introduced the concept of uncertainty
into the laws of the physical world, incomplete. His deterministic view is illustrated in the famous quote "I am convinced that He (God) does not play dice
." Einstein viewed quantum mechanics as a means simply to the end of a unified field theory
, which would unite the disparate theories of quantum field theory
, general relativity
, and electromagnetism
. However, he never denied that quantum mechanics was very successful in explaining and predicting physical phenomena.
The quest for a unified field theory is continuing with work into quantum mechanics
, string theory
, and superconductivity
. The year recognizes the fundamental shift in natural philosophy
from a theory of the absolute to that of the uncertainty and relativity spurred by Einstein's 1905 work.
Albert Einstein
Albert Einstein was a German-born theoretical physicist who developed the theory of general relativity, effecting a revolution in physics. For this achievement, Einstein is often regarded as the father of modern physics and one of the most prolific intellects in human history...
"Miracle Year
Annus Mirabilis Papers
The Annus Mirabilis papers are the papers of Albert Einstein published in the Annalen der Physik scientific journal in 1905. These four articles contributed substantially to the foundation of modern physics and changed views on space, time, and matter...
," in which he published four landmark papers, and the subsequent advances in the field of physics
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
.
History
PhysicsPhysics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
has been the basis for understanding the physical world and nature as a whole. The applications of physics are the basis for much of today's technology. In order to both raise the worldwide awareness of physics and celebrate the major advances made in the field, the International Union of Pure and Applied Physics resolved that 2005 should be commemorated as the World Year of Physics. This has subsequently been endorsed by both the United Nations
United Nations
The United Nations is an international organization whose stated aims are facilitating cooperation in international law, international security, economic development, social progress, human rights, and achievement of world peace...
and the United States Congress
United States Congress
The United States Congress is the bicameral legislature of the federal government of the United States, consisting of the Senate and the House of Representatives. The Congress meets in the United States Capitol in Washington, D.C....
http://www.theithacajournal.com/news/stories/20050514/localnews/2136011.html.
Annus Mirabilis
The year 2005 is significant primarily because of the changes that have occurred in the philosophy of physics over the past 100 years. These changes began in 1905 with the publication of four papers by Einstein that: explained Brownian motionBrownian motion
Brownian motion or pedesis is the presumably random drifting of particles suspended in a fluid or the mathematical model used to describe such random movements, which is often called a particle theory.The mathematical model of Brownian motion has several real-world applications...
, introduced the special theory of relativity, and described how the photoelectric effect
Photoelectric effect
In the photoelectric effect, electrons are emitted from matter as a consequence of their absorption of energy from electromagnetic radiation of very short wavelength, such as visible or ultraviolet light. Electrons emitted in this manner may be referred to as photoelectrons...
could be explained by the quantization
Quantization (physics)
In physics, quantization is the process of explaining a classical understanding of physical phenomena in terms of a newer understanding known as "quantum mechanics". It is a procedure for constructing a quantum field theory starting from a classical field theory. This is a generalization of the...
of light, which helped launch quantum mechanics
Quantum mechanics
Quantum mechanics, also known as quantum physics or quantum theory, is a branch of physics providing a mathematical description of much of the dual particle-like and wave-like behavior and interactions of energy and matter. It departs from classical mechanics primarily at the atomic and subatomic...
, and developed E = mc2. These papers are commonly called his Annus Mirabilis Papers
Annus Mirabilis Papers
The Annus Mirabilis papers are the papers of Albert Einstein published in the Annalen der Physik scientific journal in 1905. These four articles contributed substantially to the foundation of modern physics and changed views on space, time, and matter...
because they later defined 1905 as a miracle year for physics.
Most physicists agree that the first three of those papers deserved Nobel Prize
Nobel Prize
The Nobel Prizes are annual international awards bestowed by Scandinavian committees in recognition of cultural and scientific advances. The will of the Swedish chemist Alfred Nobel, the inventor of dynamite, established the prizes in 1895...
s, but only the paper on the photoelectric effect would win one. What makes these papers remarkable is that, in each case, Einstein boldly took an idea from theoretical physics to its logical consequences and managed to explain experimental results that had baffled scientists for decades.
Photoelectric effect
The first paper proposed the idea of "energy quantaPhoton
In physics, a photon is an elementary particle, the quantum of the electromagnetic interaction and the basic unit of light and all other forms of electromagnetic radiation. It is also the force carrier for the electromagnetic force...
" and showed how it could be used to explain such phenomena as the photoelectric effect
Photoelectric effect
In the photoelectric effect, electrons are emitted from matter as a consequence of their absorption of energy from electromagnetic radiation of very short wavelength, such as visible or ultraviolet light. Electrons emitted in this manner may be referred to as photoelectrons...
. The idea of energy quanta was motivated by Max Planck
Max Planck
Max Karl Ernst Ludwig Planck, ForMemRS, was a German physicist who actualized the quantum physics, initiating a revolution in natural science and philosophy. He is regarded as the founder of the quantum theory, for which he received the Nobel Prize in Physics in 1918.-Life and career:Planck came...
's earlier derivation of the law of black-body radiation by assuming that luminous energy
Radiant energy
Radiant energy is the energy of electromagnetic waves. The quantity of radiant energy may be calculated by integrating radiant flux with respect to time and, like all forms of energy, its SI unit is the joule. The term is used particularly when radiation is emitted by a source into the...
could only be absorbed or emitted in discrete amounts, called quanta. Einstein showed that, by assuming that light
Light
Light or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...
actually consisted of discrete packets, he could explain the mysterious photoelectric effect.
The idea of light quanta contradicted the wave theory of light that followed naturally from James Clerk Maxwell
James Clerk Maxwell
James Clerk Maxwell of Glenlair was a Scottish physicist and mathematician. His most prominent achievement was formulating classical electromagnetic theory. This united all previously unrelated observations, experiments and equations of electricity, magnetism and optics into a consistent theory...
's equations for electromagnetic
Electromagnetism
Electromagnetism is one of the four fundamental interactions in nature. The other three are the strong interaction, the weak interaction and gravitation...
behavior and, more generally, the assumption of infinite divisibility
Infinite divisibility
The concept of infinite divisibility arises in different ways in philosophy, physics, economics, order theory , and probability theory...
of energy in physical systems. Even after experiments showed that Einstein's equations for the photoelectric effect were accurate, his explanation was not universally accepted. However, by 1921, when he was awarded the Nobel Prize and his work on photoelectricity was mentioned by name in the award citation, most physicists thought that light quanta were possible. A complete picture of the photoelectric effect was only obtained after the maturity of quantum mechanics.
Brownian motion
His second article that year delineated a stochasticStochastic
Stochastic refers to systems whose behaviour is intrinsically non-deterministic. A stochastic process is one whose behavior is non-deterministic, in that a system's subsequent state is determined both by the process's predictable actions and by a random element. However, according to M. Kac and E...
model of Brownian motion
Brownian motion
Brownian motion or pedesis is the presumably random drifting of particles suspended in a fluid or the mathematical model used to describe such random movements, which is often called a particle theory.The mathematical model of Brownian motion has several real-world applications...
. Brownian motion generates expressions for the root mean square
Root mean square
In mathematics, the root mean square , also known as the quadratic mean, is a statistical measure of the magnitude of a varying quantity. It is especially useful when variates are positive and negative, e.g., sinusoids...
displacement
Displacement (vector)
A displacement is the shortest distance from the initial to the final position of a point P. Thus, it is the length of an imaginary straight path, typically distinct from the path actually travelled by P...
of particles. Using the then-controversial kinetic theory of fluids, it established that the phenomenon, which still lacked a satisfactory explanation decades after it was first observed, provided empirical evidence for the reality of atom
Atom
The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons...
s. It also lent credence to statistical mechanics
Statistical mechanics
Statistical mechanics or statistical thermodynamicsThe terms statistical mechanics and statistical thermodynamics are used interchangeably...
, which was also controversial at the time.
Before this paper, atoms were recognized as a useful concept, but physicists and chemists hotly debated whether atoms were real entities. Einstein's statistical discussion of atomic behavior gave experimentalists a way to count atoms by looking through an ordinary microscope. Wilhelm Ostwald
Wilhelm Ostwald
Friedrich Wilhelm Ostwald was a Baltic German chemist. He received the Nobel Prize in Chemistry in 1909 for his work on catalysis, chemical equilibria and reaction velocities...
, one of the leaders of the anti-atom school, later told Arnold Sommerfeld
Arnold Sommerfeld
Arnold Johannes Wilhelm Sommerfeld was a German theoretical physicist who pioneered developments in atomic and quantum physics, and also educated and groomed a large number of students for the new era of theoretical physics...
that he had been converted to a belief in atoms by Einstein's complete explanation of Brownian motion.
Special relativity
Einstein's third paper that year was a highly self-contained work, hardly making reference to other works which may have led to its development. This paper introduced a theory of time, distance, mass and energy which was consistent with electromagnetismElectromagnetism
Electromagnetism is one of the four fundamental interactions in nature. The other three are the strong interaction, the weak interaction and gravitation...
, but omitted the force of gravity.
Michelson-Morley experiment
The Michelson–Morley experiment was performed in 1887 by Albert Michelson and Edward Morley at what is now Case Western Reserve University in Cleveland, Ohio. Its results are generally considered to be the first strong evidence against the theory of a luminiferous ether and in favor of special...
failed to measure a speed difference between perpendicular light beams, by postulating that the speed of light
Speed of light
The speed of light in vacuum, usually denoted by c, is a physical constant important in many areas of physics. Its value is 299,792,458 metres per second, a figure that is exact since the length of the metre is defined from this constant and the international standard for time...
is not relative to some medium and is the same for all observers irrespective of their relative velocities. This is unlike all other known wave
Wave
In physics, a wave is a disturbance that travels through space and time, accompanied by the transfer of energy.Waves travel and the wave motion transfers energy from one point to another, often with no permanent displacement of the particles of the medium—that is, with little or no associated mass...
s, which require a medium (such as water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
or air) to propagate.
Einstein's explanation arises from two postulates: The first is Galileo
Galileo Galilei
Galileo Galilei , was an Italian physicist, mathematician, astronomer, and philosopher who played a major role in the Scientific Revolution. His achievements include improvements to the telescope and consequent astronomical observations and support for Copernicanism...
's idea that the laws of nature are the same for all observers that move with constant velocity relative to each other. The second was that the speed of light
Speed of light
The speed of light in vacuum, usually denoted by c, is a physical constant important in many areas of physics. Its value is 299,792,458 metres per second, a figure that is exact since the length of the metre is defined from this constant and the international standard for time...
is the same for every observer.
Special relativity has several striking consequences, because the concepts of absolute time and space
Absolute time and space
Originally introduced by Sir Isaac Newton in the Philosophiæ Naturalis Principia Mathematica, the concepts of absolute time and space provided a theoretical foundation that facilitated Newtonian mechanics...
are incompatible with an absolute speed of light. The theory abounds with paradox
Paradox
Similar to Circular reasoning, A paradox is a seemingly true statement or group of statements that lead to a contradiction or a situation which seems to defy logic or intuition...
es and appeared to make little sense, landing Einstein substantial ridicule, but he eventually managed to work out the apparent contradictions and solve the problems.
Consequences
Einstein's special theory of relativity heralded a new kind of physics, one that digressed from the classical mechanics that had been derived from NewtonIsaac Newton
Sir Isaac Newton PRS was an English physicist, mathematician, astronomer, natural philosopher, alchemist, and theologian, who has been "considered by many to be the greatest and most influential scientist who ever lived."...
's calculus
Calculus
Calculus is a branch of mathematics focused on limits, functions, derivatives, integrals, and infinite series. This subject constitutes a major part of modern mathematics education. It has two major branches, differential calculus and integral calculus, which are related by the fundamental theorem...
. Although his 1905 paper on the photoelectric effect helped spur the development of quantum mechanics, Einstein himself considered quantum theory, which introduced the concept of uncertainty
Uncertainty principle
In quantum mechanics, the Heisenberg uncertainty principle states a fundamental limit on the accuracy with which certain pairs of physical properties of a particle, such as position and momentum, can be simultaneously known...
into the laws of the physical world, incomplete. His deterministic view is illustrated in the famous quote "I am convinced that He (God) does not play dice
Dice
A die is a small throwable object with multiple resting positions, used for generating random numbers...
." Einstein viewed quantum mechanics as a means simply to the end of a unified field theory
Unified field theory
In physics, a unified field theory, occasionally referred to as a uniform field theory, is a type of field theory that allows all that is usually thought of as fundamental forces and elementary particles to be written in terms of a single field. There is no accepted unified field theory, and thus...
, which would unite the disparate theories of quantum field theory
Quantum field theory
Quantum field theory provides a theoretical framework for constructing quantum mechanical models of systems classically parametrized by an infinite number of dynamical degrees of freedom, that is, fields and many-body systems. It is the natural and quantitative language of particle physics and...
, general relativity
General relativity
General relativity or the general theory of relativity is the geometric theory of gravitation published by Albert Einstein in 1916. It is the current description of gravitation in modern physics...
, and electromagnetism
Electromagnetism
Electromagnetism is one of the four fundamental interactions in nature. The other three are the strong interaction, the weak interaction and gravitation...
. However, he never denied that quantum mechanics was very successful in explaining and predicting physical phenomena.
The quest for a unified field theory is continuing with work into quantum mechanics
Quantum mechanics
Quantum mechanics, also known as quantum physics or quantum theory, is a branch of physics providing a mathematical description of much of the dual particle-like and wave-like behavior and interactions of energy and matter. It departs from classical mechanics primarily at the atomic and subatomic...
, string theory
String theory
String theory is an active research framework in particle physics that attempts to reconcile quantum mechanics and general relativity. It is a contender for a theory of everything , a manner of describing the known fundamental forces and matter in a mathematically complete system...
, and superconductivity
Superconductivity
Superconductivity is a phenomenon of exactly zero electrical resistance occurring in certain materials below a characteristic temperature. It was discovered by Heike Kamerlingh Onnes on April 8, 1911 in Leiden. Like ferromagnetism and atomic spectral lines, superconductivity is a quantum...
. The year recognizes the fundamental shift in natural philosophy
Natural philosophy
Natural philosophy or the philosophy of nature , is a term applied to the study of nature and the physical universe that was dominant before the development of modern science...
from a theory of the absolute to that of the uncertainty and relativity spurred by Einstein's 1905 work.
Selected celebrations
- In the United StatesUnited StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
, the University of MarylandUniversity of Maryland, College ParkThe University of Maryland, College Park is a top-ranked public research university located in the city of College Park in Prince George's County, Maryland, just outside Washington, D.C...
sponsored several activities in cooperation with the Smithsonian InstitutionSmithsonian InstitutionThe Smithsonian Institution is an educational and research institute and associated museum complex, administered and funded by the government of the United States and by funds from its endowment, contributions, and profits from its retail operations, concessions, licensing activities, and magazines...
and NASANASAThe National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
's Goddard Space Flight CenterGoddard Space Flight CenterThe Goddard Space Flight Center is a major NASA space research laboratory established on May 1, 1959 as NASA's first space flight center. GSFC employs approximately 10,000 civil servants and contractors, and is located approximately northeast of Washington, D.C. in Greenbelt, Maryland, USA. GSFC,...
, including various lecture series and resident programs. University of Maryland Celebration. - In BerlinBerlinBerlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...
, sixteen large, red E's have been erected along a section of the famous Unter den LindenUnter den LindenUnter den Linden is a boulevard in the Mitte district of Berlin, the capital of Germany. It is named for its linden trees that line the grassed pedestrian mall between two carriageways....
boulevard. Called the "Einstein Mile", the E's , which has been in place from April to September 2005 displaying information on the theories and life of Albert Einstein. - In EgyptEgyptEgypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...
, the Library of AlexandriaLibrary of AlexandriaThe Royal Library of Alexandria, or Ancient Library of Alexandria, in Alexandria, Egypt, was the largest and most significant great library of the ancient world. It flourished under the patronage of the Ptolemaic dynasty and functioned as a major center of scholarship from its construction in the...
organized the Einstein SymposiumEinstein SymposiumIn the centennial of "Annus Mirabilis" of 1905 , the UNESCO designated year 2005 to be the World Year of Physics .Bibliotheca Alexandrina, the newly revived Library of Alexandria in...
. - San MarinoSan MarinoSan Marino, officially the Republic of San Marino , is a state situated on the Italian Peninsula on the eastern side of the Apennine Mountains. It is an enclave surrounded by Italy. Its size is just over with an estimated population of over 30,000. Its capital is the City of San Marino...
issued a €2 commemorative coin. - The KirwitzerWenceslas Pantaleon KirwitzerWenceslas Pantaleon Kirwitzer was an astronomer and a Jesuit missionary.- Life :Kirwitzer was born in Kadaň , Bohemia to a protestant family descended from the village of Krbice so his surname was derived from "Kürbitzer"...
Day 2005 in KadaňKadanKadaň , is a city in the Ústí nad Labem Region of the Czech Republic.The city lies on the banks of the river Ohře. Although it is situated in an industrial part of the Czech Republic there is no major industry within the city and people usually work in offices or have to commute. There are two...
, the Czech RepublicCzech RepublicThe Czech Republic is a landlocked country in Central Europe. The country is bordered by Poland to the northeast, Slovakia to the east, Austria to the south, and Germany to the west and northwest....
, was dedicated to Einstein's theories. - The Perimeter Institute for Theoretical PhysicsPerimeter Institute for Theoretical PhysicsPerimeter Institute for Theoretical Physics is an independent, resident-based research institute devoted to foundational issues in theoretical physics located in Waterloo, Ontario, Canada. Perimeter Institute was founded in 1999 by Mike Lazaridis...
, Waterloo, OntarioWaterloo, OntarioWaterloo is a city in Southern Ontario, Canada. It is the smallest of the three cities in the Regional Municipality of Waterloo, and is adjacent to the city of Kitchener....
, CanadaCanadaCanada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, hosted Einstein Fest from September 30 to October 23 http://www.perimeterinstitute.ca/activities/community/einsteinfest/. - Beyond Einstein World Wide WebcastBeyond Einstein World Wide WebcastBeyond Einstein World Wide Webcast was a webcast held on December 1, 2005 about the current physical challenges related to the theories of Albert Einstein....
, organized by CERNCERNThe European Organization for Nuclear Research , known as CERN , is an international organization whose purpose is to operate the world's largest particle physics laboratory, which is situated in the northwest suburbs of Geneva on the Franco–Swiss border...
, was held on December 1, 2005.