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Einstein: 100 Years of Relativity
By London 2005
"I want to know how God created this world. I am not interested in this or that phenomenon, in the spectrum of this or that element. I want to know His thoughts; the rest are details." -- Albert Einstein
E = mc2 is arguably the most recognizable scientific equation in the world. From learned scholars to pedestrian commentators, this equation and the person who postulated it became signposts to the moment that man sought to unravel the secrets of creation. It became the first scientific equation to hit the street and be shared by users and admirers alike. It is not hidden in some obscure, dusty library nor is it the exclusive preserve of scientific academics in the renowned universities of the world.
This week marks the 100th year anniversary of the publication of Albert Einstein's Theory of Relativity. This diminutive, clownish character was named as man of the century by the Time magazine in the millennium year 2000 due to the impact this theory has made on the world. While Newton's laws of motion and gravitational attraction were phenomenal, the jurists who decided on Albert Einstein for Time magazine believed that even without Newton, the laws he postulated would still have been discovered as they were observational while on the other hand it would have taken almost eternity for anybody to have theorized what Einstein did. Einstein became the personification of the nerdy scientist long before the word nerd was in fashion. He became one of the most recognizable faces and the most quoted individuals of the last century.
Little Albert started life in the little town of Ulm in Germany on March 14, 1879. In 1894 Albert's parents, non practicing Jews, immigrated to Milan, Italy when their business failed in 1894. Albert remained in Munich to continue his education. A year later he failed an examination for entry into Swiss Federal Institute of Technology to study for a diploma in Electrical Engineering. After a year of further study at a secondary school in the nearby town of Aarau, Albert was able to gain entry into the Swiss Federal Institute of Technology where he graduated as a teacher of Mathematics and Physics in the 1900.
For seven years, between 1902 and 1909, he worked at the Swiss Patent office where he made astonishing publications in theoretical physics with no benefit of a scientific community or literature. As this was not part of his job, his observations and theories were done in his spare time. In 1905 he submitted one of his papers to the University of Zurich and he was immediately awarded a Ph.D. degree. In 1909, he accepted regular employment as a professor of physics from that university and left the Patent Office. Between 1909 and 1914 he was a Professor of Physics in the German University of Prague, Swiss Federal Institute of Technology and the prestigious Kaiser-Wilhelm Gesellschaft in Berlin.
It was in 1905 at the age of 26 that his Theory of Relativity was born. It was in June of that year that he submitted his paper titled "On the Electrodynamics of Moving Bodies" to a leading German physics journal. He applied the same theory as contained in the paper to the concepts of mass and energy and the most famous and celebrated equation in science E=mc2 was formulated. Meanwhile, Albert was still working as a Patent Clerk at the Swiss Patent Office in Bern, Switzerland.
He was the youngest to attend the first world physics conference in 1911 held in Solvay, Brussels.
In 1921 at the age of 42 Albert Einstein was awarded the Nobel Prize in Physics. He was awarded the prize, according to the Nobel Committee, "for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect". The law of photoelectric effect discusses the emission of electrons by substances, especially metals, when light falls on their surfaces. The effect was discovered by H. R. Hertz in 1887. Quantum Physics evolved out of the failure of theory of electromagnetic radiation to explain this law of photoelectric effect.
Einstein was not given Nobel Prize as recognition of his Theory of Relativity because it took controversial dimensions when viewed by the clergy and the non-scientific community. Einstein was blamed for introducing moral relativism and the discarding of moral absolutes in the perception of good or bad in society. Suffice it to say, Albert Einstein’s theory is far removed for any religious or social benchmark. But our friends in Oslo did not want to offend anybody.
For someone whose second grade music teacher once told, "Albert, you just can't count," due to his inability to keep track of musical notes, our little Albert had indeed came a long way.
A late developer, Albert Einstein credited his early slow progress for his fascination with space-time problems. Says he, "the ordinary adult never gives a thought to space-time problem. I, on the contrary, developed so slowly that I did not begin to wonder about space and time until I was an adult. I then delved more deeply into the problem than any other adult or child would have done."
Now living in Germany, a celebrated international figure and an avowed pacifist, Albert Einstein was identified as a Jew and he began feeling the heat of Nazi Germany. He immigrated to the United States and settled in the University community of Princeton New Jersey where he took a position at the Institute for Advanced Study.
Albert Einstein's General Theory of Relativity (1915) and later Unified Field Theory which he started working on in 1928 were built on the works of earlier physicists such as a Galileo, Newton, Boltzmann, Gibbs, Maxwell, Faraday, Lavoisier, Cassinni, Max Planck, Bohr and Roemer. Einstein had realized earlier that the two pillars of physics; Newtonian mechanics (where velocities can be added and subtracted) and the Maxwellian electromagnetic theory (where the speed of light was constant) were in total contradiction. One of the two theories had to be wrong. And if so, it would require the abandonment of some of the theoretical structures of physics.
Einstein also knew that, according to an earlier theory of electrons (By Lorentz), the mass of an electron increased as the velocity of the electron approached the velocity of light. Einstein realized that the equations describing the motion of an electron in Lorentz’s theory could, in fact, describe the non-accelerated motion of any particle or any suitably defined body.
The conflict of the two scientific positions was still preying on Einstein’s mind when one evening while driving home in a streetcar in Bern, Switzerland, he looked back at the famous clock tower that dominated the city. He then imagined what would happen if his streetcar raced away from the clock tower at the speed of light. He quickly realized that the clock would appear stopped but his own clock in the streetcar would beat normally. The solution to the problem that had been on his mind came to him in a flash. That was his “eureka” moment and he would later recall that this begins the birth of the Special Relativity Theory. He recalled further that it was like a storm breaking loose in his mind. The answer was simple and elegant: Time can beat at different rates throughout the universe, depending on how fast you moved. Imagine clocks scattered at different points in space, each one announcing a different time, each one ticking at a different rate. One second on Earth was not the same length as one second on the moon or one second on Jupiter. In fact, the faster you moved, the more time slowed down. This observation debunks Newton’s theory.
This meant that events that were simultaneous in one frame were not necessarily simultaneous in another frame, as Newton thought. Einstein would recall excitedly, "The solution came to me suddenly with the thought that our concepts and laws of space and time can only claim validity insofar as they stand in a clear relation to our experiences." If we are to semantically simplify Einstein's theory the same way Newton's laws were, we could say that "when a body travels at the speed of light, time slows down (remember the clock on the tower) and the body gets squashed in the direction of travel (remember Lorentz's theory of accelerating electrons above)". Lorentz’s work, later termed “Lorentz’s Contraction” agrees that measurements made in one uniformly moving system can be correlated with measurements in another system if the velocity of one relative to the other is known. But it is neither that simplistic nor would this simplified explanation give justice to the equation of relativity.
So let's try again: When you are sitting still in a stationary vehicle adjacent to another stationary vehicle and your vehicle suddenly starts moving, for a split second you would not be able to tell if it is your vehicle or the other vehicle that is moving. Or putting it another way, if both vehicles are moving in the same direction at the same speed, it would seem to you that both vehicles are stationary. Now, if the two vehicles are moving past each other in opposite directions at the same speed, it would seem as if your vehicle is moving at twice its current speed relative to the other vehicle. These statements agree with the existence of a state of ABSOLUTE MOTION OR REST (hence the word "stationary") and the concept of TIME which measures speed and which in turn is measured by clocks. Up to this point Einstein’s theory of relativity agrees with the concepts of absolute rest and a defining frame of reference for the calculation of speed against time for bodies in space.
However, Einstein postulated that at very, very high speeds (like the speed of light) the two clocks in the two vehicles will read different times if the vehicles are moving at different speeds, in different directions or if one of them is not moving at all. This postulation discards the concept of absolute motion or absolute frame of reference as proffered by Galileo and Newton and instead treats only relative motion between two systems or frames of reference. One consequence of the theory is that space and time are no longer viewed as separate, independent entities but rather are seen to form a four-dimensional continuum called space-time.
Einstein’s Special Theory of Relativity accepts the hypothesis proffered by Lorentz in his work that the measured speed of light is constant for all observers regardless of the motion of the observer or of the source of the light. So the speed of light became the unachievable target based on which the speed of moving bodies is benchmarked.
As Stephen Hawking, the renowned English scientist explains in his Book, "A Brief History of Time", if you bounce a ball in a fast moving train, the ball is likely to drop in the same spot it bounced up from even though during the time it took it to drop back to that spot the train must have moved a certain distance. But the ball does not know that because it is moving at the same speed with the train although in the eyes of a person standing in the train it is in one place. The ball does not experience the speed of the train because in relation to the speed of the train the ball which is in the same train is stationary.
Einstein postulation that the laws of nature should appear the same to all freely moving observers in a common frame of reference was the foundation of the theory of relativity, so called because it implies that only relative motion is important. In the above analogy of the ball in a train, the vertical bouncing motion of the ball is more important to the ball and the person bouncing it than the horizontal movement of the speeding train.
Einstein's theory brought together and explained the inter-relationships between the concepts of physical mass, time, energy and space. So a better way to look at its impact would be to look at some real-life (although in some cases, microscopic) consequences of his work.
Because Einstein postulated that the speed of light should appear the same to everyone, this implied that nothing could move faster than light. So while in most phenomena of ordinary experience the results obtained from the application of the Special Theory approximate those based on Newtonian dynamics (that the concept of absolute speed exists), the results deviate greatly for actions or processes occurring at velocities approaching the speed of light.
To propel a body to move at the speed of light would require an infinite amount of energy because according to the theory of relativity the mass of a body increases as energy is used to accelerate it. The equivalence of mass and energy is summed up in the equation, E=mc2. Where E is energy, m is mass and c is the speed of light. In a nutshell, this equation states that mass and energy are interchangeable. The C (or speed of light, which is 670,000,000 miles per hour) is a constant. This means that if the body in question is a grain of rice of mass 5 milligrams, the grain of rice has the potential of emitting energy that is the square of 670,000,000 multiplied by its mass. The square of the speed of light is 448,900,000,000,000,000.
So ask yourself, how much energy is captured within a piece of groundnut or cement brick? I don't know for the brick but the energy contained in one piece of groundnut is more than the energy released by the bomb dropped on Hiroshima in 1945. The brick in question could have enough energy trapped in it to power the city of London with electricity for a week. A lump of coal the same size as light bulb can have trapped within it enough power to light the same bulb for over twenty million years. If you burn the same coal in a conventional power plant for the purpose of generating energy, it could only power the same bulb for 60 hours. We are still stuck with the conventional method, anyway, as there is still no practical way of efficiently extracting energy due to the mass of these bodies of matter. After a hundred years the Theory of Relativity is still a theory.
And because, as stated earlier, mass and energy are interchangeable, a space shuttle moving at roughly 18,000 miles per hour will have an added mass due to its energy of propulsion. The energy added to the shuttle at this speed will be equivalent to the mass of a housefly.
A practical consequence of this equation is that if the nucleus of a uranium atom splits into two nuclei with slightly less total mass, a tremendous amount of energy is released. This gave birth to the atomic bomb.
To study the large effects of gravitation, Einstein discovered that in the geometry of a given region of space and the motion in the field can be predicted from the equations of the General Theory of Relativity which is an expansion of his Special Theory of Relativity. Because details of the motions of the planet Mercury had long puzzled astronomers; Einstein's computations using his expanded theory explained them. He stated that the path of a ray of light is deflected by a gravitational field. He predicted that in a gravitational field, spectral lines of substances would be shifted toward the red end of the spectrum. This was confirmed by observations made in 1919 by A S Eddington during a solar eclipse and more recently by measurements carried out by the craft Viking when it landed on the planet Mars. Eddington’s observation in 1919 was of immense important as it became the first practical proof of Einstein’s General Theory of Relativity.
This theory also gave birth to space science, emission scans in hospitals and a million and one other discoveries and phenomena that we now take for granted. Einstein’s work one hundred years ago has changed our world more than any scientific work before or after it. It has impacted on everything we do as scientists since then. From the splitting of the atom to the human genome project.
Albert Einstein died of heart failure in Princeton New Jersey on April 16, 1955. His body was cremated and his brain has been preserved at the Princeton University. He was 76 years old.
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