Einstein S Theories of Relativity

Einstein’s Theories of Relativity

"My interest in science was always essentially limited to the study of principles.... That I have published so little is due to this same circumstance, as the great need to grasp principles has caused me to spend most of my time on fruitless pursuits."

Albert Einstein is the author of the special and general theories of relativity. He was born in 1879 in Germany. In 1905, Einstein proposed the special theory of relativity. In 1916, he published the General Theory of Relativity. Einstein’s special theory of relativity has had experimental data agree with the theory. In 1919, Einstein’s general theory of relativity had experimental data verify the general theory of relativity. However, Einstein’s general theory of relativity is still undergoing experimental tests since it may be the least tested of Einstein’s theories.

Special Theory of Relativity

Einstein published the special theory of relativity in 1905. There are two postulates of special theory of relativity.The relativity postulate is the laws of physics are the same for all observers in all inertial reference frames and no one frame is preferred over any other. The speed of light postulate is the speed of light in vacuum has the same value c in all directions and in all inertial reference frames. Under the two postulates special relativity has yielded a four coordinate system including x, y, z, and t, the relativity of simultaneity, the relativity of time (time dilation), the relativity of length (length contraction), the Lorentz Transformation, the relativity of velocities, the Doppler effect for light, and momentum and energy.

The special theory of relativity yields one of the most well known equations E = mc². Total energy E of an isolated system cannot change by the conservation of energy. In fusion and fission E = γmc² is used where γ is the Lorentz factor of the particle in motion where the equation can be expressed in other relationships. When a particle or particles fuse or undergo(es) fission energy is released as radiation energy and mass energy.

General Theory of Relativity

Einstein published the general theory of relativity in 1915-1916. There is one postulate of general theory of relativity. The relativity postulate is gravitation is equivalent to acceleration where gravity does not depend on the properties of matter rather gravity must take place from the properties of space-time. Gravitational mass of a body is equal to its inertia mass. Newton’s law of motion:

(Force) = (inertial mass) Х (acceleration)

The “inertial mass” is a characteristic constant of the accelerated body. If now gravitation is the cause of the acceleration:

(Force) = (gravitational mass) X (intensity of the gravitational field)

The “gravitational mass” is a characteristic constant for the body. Therefore:

(acceleration) = (gravitational mass) X (intensity of the gravitational field)

(inertial mass)

Einstein used his famous “thought experiment” to explain the relationship between gravity and space-time. The general theory of relativity has been described as, “matter tells space-time how to curve, and curved space-time tells matter how to move.” Einstein has gravitational field equations that describe mathematically how space-time is curved by matter and energy.

Experiments

E = mc² has been verified and most recognized by the atomic bomb. In fact, Einstein’s relationship of mass, energy, and light is verified every day by nuclear power plants all over the world. In 1919, May 29 a solar eclipse occurs and verified Einstein’s general theory of relativity. Einstein predicted that light-bending can be observed during a solar eclipse which was verified in 1919 by Arthur S. Eddington. Albert predicted gravitational waves transmit gravitational force which was observed by scientist in a pair of neutron stars that orbit each other. The stars emitted gravitational waves which distorted space-time. In the 1970’s NASA already verified Einstein’s general theory of relativity by experimentally testing the Einstein redshift prediction. Currently, the National Aeronautics and Space Administration (NASA) is experimentally testing the general theory of relativity in two ways including the geodetic effect (the amount by which the Earth warps the local spacetime in which it resides) and the frame-dragging effect (the amount by which the rotating Earth drags its local spacetime around with it).

Conclusion

Einstein’s special and general theories of relativity are a large part of modern physics. A few scientists before Einstein toyed with the special theory of relativity but in 1905 Einstein showed the world he had grasped the theory that relates mass, energy, time, and space. However, in 1915-1916 Einstein grasped the theory that generalizes the law of gravity before many other scientists. It is said that if Einstein had not published the general theory of relativity it would have been years or decades and teams of scientists to come to the theory. Now, a quote from Einstein himself, "the important thing is not to stop questioning. Curiosity has its own reason for existing. One cannot help but be in awe when he contemplates the mysteries of eternity, of life, of the marvelous structure of reality. It is enough if one tries merely to comprehend a little of this mystery every day."

References

Dine, Michael. "Relativity." World Book Online Reference Center. 2004. World Book, Inc.

Einstein, Albert, Amit Hagar, and Robert W. Lawson. Relativity The Special and the General Theory. 3rd ed. New York: Barnes & Noble Publishing, Inc., 2004. Print.

Einstein, Albert. "Einstein Quotes." NOVA Science Programming on Air and Online. 01 001 1993. Carol Publishing, Web. 24 Nov 2009. <

Here is a great source to learn about and use Einstein’s theories:

Halliday, David, Robert Resnick, and Jearl Walker. Fundamentals of Physics. 8th ed., Extended. 2 vols. Hoboken, NJ: John Wiley & Sons, Inc., 2008. 1022-49. Print.

Einstein and Gravitation: page 347-348.

Relativity: page 1022-1056.

Overduin, James. "Einstein's Spacetime." Gravity Probe B: Testing Einstein's Universe. 01 011 2007. Stanford University, Web. 24 Nov 2009. <

Overduin, James. "Testing Einstein." Gravity Probe B: Testing Einstein. 01 012 2007. Stanford University, Web. 24 Nov 2009. <

"Overview of the GP-B Mission." Gravity Probe B: Testing Einstein. 01 005 2007. Stanford University, Web. 25 Nov 2009. <

Miller, William. "Einstein Quotes." NOVA Science Programming on Air and Online. 02 005 1955. NOVA, Web. 24 Nov 2009. <

Photo Source: