A very special birthday on the 21st Nov. 2005. E=MC^2 turned 100 years old!!
This equation was part of a paper submitted by an unknown clerk at the Swiss Patent Office. By the end of the 20th century, this clerk was, consistently, in all the lists of the most influential person of century. He put forth three theories (photoelectric effect, Brownian movement and relativity) in one year! This year, 1905, is now know as the “miracle year” and UNESCO has decided to call the year 2005 the “World Year Of Physics” coinciding with the 100th year of release of the three papers (collectively called Annus Mirabilis Papers). What is astonishing is the fact that Einstein did not use any experimental data or physical data in constructing these theories. He used logical reasoning. No one had done this before and after this, the path to cosmology was revealed.
This equation still confounds scientists. What does it mean? “The energy that can be obtained from an object is equal to it’s mass times twice the speed of light” This is the simplistic form of explanation that laymen like us can understand. But it goes deeper than that.
The main thing about this theory is not the theory itself, but the postulates that Einstein put forth. The two postulates were :-
Laws of physics are the same at all times and in all frames of reference i.e. laws of physics and mathematics stay the same to all observers, moving or stationary.
- Speed of light in vacuum is always the same no matter who is recording the speed and how. IT ALWAYS STAYS THE SAME.
These two postulates have been confirmed independently by experiments and they are now a fact in modern physics. On the basis of these two postulates, Einstein came up with the Special Theory Of Relativity. This theory not only modified the notion of space and time, but also the concept of mass, momentum and energy. Special theory of relativity showed that as space and time are inter-related, these aspects of an object are different representation of the same physical quality thereby overturning the Newtonian physics forever.
This equation has had a huge direct effect on our society as well. Since the equation says that energy and mass are basically the same thing, therefore, mass of an object can be converted into energy. By comparing the mass of different atomic nuclei and comparing that mass with the mass of protons and neutrons, one can calculate the energy within an atomic nuclei. This is the basis of an atomic bomb. And it was Einstein who urged President Roosevelt to pursue the study of nuclear fission in 1939 before Hitler did it. As a result of that letter, the Manhattan Project was initiated and the rest is history. It has to be said that Einstein did later recant his support for atomic bombs and famously said “I don’t know how the World War III will be fought but I do know that the World War IV will be fought with sticks and stones.”