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Biography of Albert Einstein | Theory of relativity


It revolutionized the science with the theory of relativity, that being the concepts of space and time and matter and energy.
In the 17TH century, simplicity and elegance with which Isaac Newton had managed to explain the laws that govern the movement of the bodies and of the stars, unifying the celestial and terrestrial physics dazzled to such an extent to his contemporaries who came to be deemed completed mechanics. At the end of the 19th century, however, was already inevitable the relevance of phenomena that classical physics could not explain. It corresponded to Albert Einstein to overcome such shortcomings with the creation of a new paradigm: the theory of relativity, starting point of modern physics.

Albert Einstein in 1947
In both that explanatory model completely away from common sense, relativity is one of those advances that, at the dawn of the 20th century, would lead to the divorce between the ordinary people and a science increasingly specialized and unintelligible. However, already in life physicist or posthumously, even more surprising and incomprehensible aspects of relativity would end up being confirmed. It should be no surprise, therefore, that Albert Einstein is one of the most famous and admired in the history of Science: knowing that are hardly conceivable so many ideas (for example, that the mass of a body increases with velocity) leaves no choice but to surrender to his genius.

A bad student

Albert Einstein was born in the Bavarian city of Ulm on March 14, 1879. He was the firstborn son of Hermann Einstein and Pauline Koch, both Jews, whose families came from Swabia. The following year they moved to Munich, where the father was established, together with his brother Jakob, as a trader in electro technical innovations of the time.
The little Albert was a child still and inward-looking, and had an intellectual development slow. The own Einstein attributed to that slow the fact of having been the only person who develop a theory like Relativity: "a normal adult is not disturbed by issues raised by space and time, because it believes that all what you need to know about know it already from his early childhood. I, on the other hand, had a development so slow that I have not started to ask me questions about space and time until I've been more».
In 1894, the economic difficulties made the family (increased from 1881 with the birth of a daughter, Maya) moved to Milan; Einstein remained in Munich to finish high school, meeting with their parents the following year. In the fall of 1896 he began his studies at the Eidgenössische Technische Hochschule Zürich, where was a pupil of the mathematician Hermann Minkowski, who subsequently generalized formalism four-dimensional introduced by the theories of his former pupil.

With his second wife, Elsa Einstein
On June 23, 1902, Albert Einstein started to provide its services in the Office Confederal the property intellectual of Berne, where he worked until 1909. In 1903, married to Mileva Maric, former companion of studies in Zurich, with whom he had two children: Hans Albert and Eduard, born in 1904 and 1910 respectively. They divorced in 1919, and Einstein married his cousin Elsa again.


During 1905, published five works in the Annalen der Physik: the first of them earned him the degree of doctor from the University of Zurich, and the remaining four would eventually impose a radical change in the image, offering the science of the universe. Of these four, the first provided a theoretical explanation, in statistical terms, of Brownian motion, and the second gave an interpretation of the photoelectric effect based on the hypothesis that light consists of many individual, later called photons. The two remaining works sat bases of restricted theory of relativity, establishing the equivalence between the energy E of a certain quantity of matter and its mass m in terms of the famous equation E = mc², where c is the speed of light, which is supposed to be constant.
The effort of Einstein immediately placed him among the most eminent European physicists, but the public recognition of the true scope of his theories took to arrive; the Nobel Prize in physics, he received in 1921, was awarded exclusively 'for his work on Brownian motion and its interpretation of the photoelectric effect". In 1909 he began his career of University teaching in Zurich, then to Prague and returning back to Zurich in 1912 to be Professor of the Polytechnic, where had studied.

Einstein playing the violin, one of his favorite hobbies (c. 1930)
In 1914 he went to Berlin as a member of the Prussian Academy of Sciences. The outbreak of the first world war forced him to separate from his family (at that time on vacation in Switzerland), who already did not meet him. Against the widespread feeling of the Berlin academic community, Einstein expressed so openly anti-war, influenced their attitudes by the pacifist doctrines of Romain Rolland.
The flat scientist, his activity focused between 1914 and 1916, in the development of the general theory of relativity, based on the postulate that gravity is not a force but a field created by the presence of a mass in the space-time continuum . The confirmation of their forecasts came in 1919, to photograph the solar eclipse of May 29; The Times introduced him as the new Newton and his international fame grew, forcing you to multiply their dissemination conferences all over the world and popularized his image of traveller's third class of railway, with a case of violin under his arm.
Toward a unifying theory
During the next decade, Einstein concentrated their efforts on finding a mathematical relationship between electromagnetism and the gravitational pull, endeavored to advance towards that, for him, was to be the ultimate goal of Physics: discover the common laws that, supposedly, had to govern the behavior of all the objects in the universe from subatomic particles to the stellar bodies , and group them into a single "unified field" theory. Such research, which occupied the remainder of his life, proved unsuccessful and eventually lead to estrangement with regard to the rest of the scientific community. From 1933, with Hitler's accession to power, his loneliness was aggravated by the need to renounce the German citizenship and moved to the United States; Einstein spent the last twenty-five years of his life in the Institute of advanced studies at Princeton (New Jersey), city where he died on April 18, 1955.
Einstein once said that the policy had a passed value, while an equation worth for all eternity. In the last years of his life, the bitterness to not find the formula that reveals the secret of the unity of the world was accentuated by the need he felt to dramatically intervene in the sphere of the political. In 1939, at the behest of the physicists Leo Szilard and Paul Wigner, and convinced of the possibility that the Germans were able to manufacture an atomic bomb, addressed to President Roosevelt urging him to undertake a program of research on atomic energy.
After the explosions of Hiroshima and Nagasaki, Einstein joined the scientists who sought to prevent the future use of the pump and proposed the formation of a world Government from the embryo consisting of the United Nations. But their proposals in favour of that humanity avoid destruction of individual and collective threats, made on behalf of a unique amalgam of science, religion and socialism, received politicians reject comparable to respectful criticism that successive versions of the idea of a unified field among scientists.
Albert Einstein remains a mythical figure of our time; more, even, of what came to be in life, if you consider that one photo yours that exhibits an unusual gesture of derision (drawing in a comic and irreverent expression language) has been elevated to the dignity of domestic icon after being converted into a common poster as idols of the song and the stars of Hollywood. However, are not his scientific genius or human size which best explain it as myth, but, perhaps, the cluster of paradoxes that holds its own biography, accented with historical perspective. The Einstein champion of pacifism he is remembered still as to the "father of the bomb"; and it is still running that the demonstration of the principle that "everything is relative" is attributed to him, who fought fiercely against the possibility of knowing the reality meant to play with it to the blind man.

Timeline of Albert Einstein

1879Born in Ulm.
1896He began his studies at the Federal Institute of Technology Zurich.
1901Acquires Swiss nationality.
1902He joined as civil servant in the Federal Patent Office in Berne.
1903She marries Mileva Maric, which will have two children.
1905He published his first articles in which deals with the fields of the Brownian motionand the photoelectric effect and special relativity.
1909Get your first place of associate professor at the University of Zurich.
1913He was appointed director of the Institute of physics Kaiser Wilhelm in Berlin.
1916It publishes the general theory of relativity.
1919Mileva divorced, he married Elsa, a cousin of his.
1920Meet Leo Szilard, who will develop inventions such as a refrigerator and an electromagnetic pump without moving parts.
1921He receives the Nobel Prize in physics.
1933Leaves Germany, lives in exile in France, Belgium, United Kingdom and United States, country this last where he is greeted with enthusiasm. There will be a Professor of theoretical physics at the Institute of superior studies at Princeton.
1939Letter to Roosevelt in which we are asked to undertake a program of research on the atomic bomb.
1940Adopt U.S. citizenship.
1945He retired from teaching in order to develop their theoretical research exclusively.
1955Dies in Princeton (USA).

Albert Einstein and the theory of relativity

The theory of relativity, developed primarily by Albert Einstein, intended originally to explain certain anomalies in the concept of relative motion, but in its evolution has become one of the most important theories in the physical sciences, and has been the basis for physicists to demonstrate the essential oneness of matter and energy, space and time , and the equivalence between the forces of gravitation and the effects of the acceleration of a system.

Albert Einstein
The theory of relativity as Einstein put it had two different formulations. The first is that which corresponds to two papers published in 1905 in the Annalen der Physik. It is known as the theory of special relativity and deals with systems that move one with respect to the other with constant speed (and may be even equal to zero). The second, called general relativity theory (this is called the work of 1916 at which made it), deals with systems moving at variable speed.

Special relativity theory

The postulates of special relativity are two. The first says that all motion is relative to anything else, and therefore the ether, which had been considered during the 19th century as average propagator of light and the only thing quite firmly of the universe, with absolute movement and not determinable, was out of place in physics, since no longer is it needed such media (whose existence effective In addition, not had been able to determine by any experiment).
The second postulate asserts that the speed of light is always constant with respect to any observer. Of their theoretical premises obtained a series of equations that had important consequences and even some disconcerting, as the increase of the mass with speed. One of its most important results was the equivalence between mass and energy, according to the famous formula E = mc², where c is the speed of light, and E represents the energy obtainable by a body of mass m when all its mass is converted to energy.

Einstein in the laboratory of Pieter Zeeman (Amsterdam, c. 1920)
The equivalence between mass and energy was demonstrated in the laboratory in 1932, and resulted in impressive concrete applications in the field of Physics: both nuclear fission and nuclear fusion are processes in which a part of the mass of the atoms is transformed into energy. Particle accelerators, which gets an increase in mass, are clear experimental proof of the theory of special relativity.
The theory also States that in a system moving with respect to an observer is verified a dilatation of the time; put another way, time passes more slowly in the system in motion. This is clearly illustrated by the famous twins paradox: "imagine twins of twenty years, and that one remained on Earth and the other departed in a ship, as fast as light, towards a distant goal thirty years Earth light; the back of the ship, to the twin who stayed on earth would have passed sixty years; on the other hand, for the other, just a few days".

Theory of general relativity

The theory of general relativity refers to the case of movements that occur with variable speed and has as a fundamental postulate the equivalence principle, according to which the effects produced by a gravitational field are equivalent to those produced by the accelerated movement.
The revolutionary hypothesis formulated by Einstein was caused by the fact that the theory of special relativity, based on the principle of the constancy of the speed of light which is the movement of the reference system which is measured (as was demonstrated in the experiment of Michelson and Morley), does not match the theory of Newtonian gravitation : If the force with which two bodies are attracted depends on the distance between them, to move one should change instantly the Force felt by the other, i.e. the interaction would have a propagation speed infinite, violating the special theory of relativity, which says that nothing can exceed the speed of light.
After several failed attempts to accommodate the gravitational interaction with relativity, Einstein suggested that gravity is not one force as the other, but it is a consequence that space-time is warped by the presence of mass (or energy, which is the same). Then, bodies like the earth does not move in closed orbits because there is a force called gravity, but they move in as close to a straight line, but in a spacetime which is distorted by the presence of the Sun.

Einstein in his Studio (c. 1925)
General relativity calculations are performed in a space-time four dimensions, three spatial and a temporal, already adopted in the theory of restricted relativity having to abandon the concept of simultaneity. However, in contrast to Minkowski space and because of the gravitational field, this universe is not Euclidean. Thus, the distance between two adjacent points of space-time in this universe is more complex than in the Minkowski space.
Planetary orbits very similar to that obtained with the mechanics of Newton are obtained with this theory. One of the points of disagreement between the two, the abnormally elongated orbit of the planet Mercury, which has an effect of rotation of the major axis of the ellipse (approximately one degree every ten thousand years), had been experimentally observed some years before stated the theory of relativity, and could not be explained with Newton's laws. The described orbit, however, fulfilled predictions relativistic, thus serving as experimental confirmation of Einstein's theory.
An effect that early corroborated the theory of general relativity is the deflection that suffer the rays of light in the presence of gravitational fields. Light rays, going from a region of a gravitational field to another, should suffer a shift on its wavelength (the gravitational red shift or displacement of Einstein), which was proven by measuring the displacement of a star, with respect to a group of stars taken as reference, apparent when light rays from it brushed the Sun.

Displacement of Einstein
To avoid the glare of the observer by the Sun's rays, verification was conducted using a total solar eclipse that took place in 1919. The star was photographed twice, one in absence and in presence of the eclipse. Thus, by measuring the apparent displacement of the star with respect to the reference stars, was obtained Deflexion angle which turned out to be very close to that Einstein envisioned.
The concept of time was deeply affected by general relativity. A surprising result of this theory is that time must elapse slower much stronger is the gravitational field in which it is measured. This prediction was also confirmed by experience in 1962. In fact, many modern satellite navigation systems take into account this effect, since otherwise they would give errors in the calculation of the position of several kilometers.
Another surprising deduction of Einstein's theory is the phenomenon of gravitational collapse which gives rise to the creation of black holes, concentrations of mass in such high density that its force of gravity traps even light. Since the gravitational potential is non-linear, to becoming the order of the square of the speed of light you can grow indefinitely, appearing a singularity in solutions. The study of black holes would become in few years in one of the research areas of increased activity in the field of cosmology; Perhaps it would be the center of interest of the fruitful hypothesis of another distinguished physicist, Stephen Hawking.
Precisely in the wake of general relativity, the cosmological models of the universe underwent a radical transformation. Relativistic Cosmology conceives a universe unlimited, devoid of limits or barriers, but finite; the space is curved in the sense that gravitational masses determine the curvature of light rays in its proximity. However, the Russian mathematician Alexander Friedmann in 1922 conceived a model that represented a universe in expansion and was also due to Einstein's relativistic equations. However, the greatest revolution of thinking that leads to the theory of general relativity is the abandonment of space and time as independent variables from the matter, which is extremely strange and apparently contrary to the experience. Before this theory the space and time were conceived as independent and as absolute references with prior to the universe existence; This intuitive "evidence" which we have in everyday life were also budgets that forcible in the mechanics of Newton and Descartes's rationalism.
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