Wednesday, 21 August 2019

On Einstein’s Formula E = MC2

Albert Einstein (1921)
Albert Einstein’s 1905 paper on the theory of relativity is a great intellectual achievement of all time. The paper contains several landmark ideas, including the famous formula E = MC2, which established for the first time that there is a direct relationship between energy and mass—all the mass in the universe is condensed energy, and all the energy in the universe is potential mass.

But E = MC2 is not a mathematical formula. Einstein did not propose it with the purpose of calculating the exact amount of energy that is released when mass is converted into energy. His aim was limited to asserting that there is a relationship between energy and mass.

In his book E = MC2: The Biography of the World’s Most Famous Formula, David Bodanis describes the origin of E = MC2 and how it has transformed our view of the universe. He notes in several chapters that E = MC2 is not a formula for computation. Here’s an excerpt from page 26:
A good computation is not simply a formula for computation. Nor is it a balance scale confirming that two terms you suspected were nearly equal really are the same. Instead, scientists started using the = symbol as something of a telescope for new ideas—a device for directing attention to fresh, unsuspecting realms. Equations simply happen to be written in symbols instead of words.  
This is how Einstein used the “=“ in his 1905 equation [E = MC2] as well. The Victorians had thought they’d found all possible sources of energy they were: chemical energy, heat energy, magnetic energy, and the rest. But by 1905 Einstein could say, No, there is another place you can look where you’ll find more. His equation was like a telescope to lead there, but the hiding place wasn’t far away in outer space. It was down here—it had been right in front of his professors all along.  
He found this vast energy source in the one place where no one had thought of looking. It was hiding away in solid matter itself. 
E = MC2 is a great intellectual achievement, but the point is that it is not used by people working in the nuclear industry to compute the yield of their nuclear reactors.

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