equations

111 years ago, Albert Einstein send on ’Annalen der Physik’ the 4th of his Annus Mirabilis papers, a three-page paper titled: “Does the Inertia of a Body Depend Upon Its Energy Content?” [PDF, wikipedia], from which it’s can be derived the famous relation E = mc².

Actually you can not find such equation in the article and rather you will find this other one, a bit ugliest (and approximate, magnitudes of fourth and higher orders are neglected):

E = mc² is not the same equation but still serves at least to illustrate the equivalence relationship between mass and energy (through the gargantuan factor ), and after all Einstein indeed explicitly wrote down this relation in the last page, but using words:

If a body gives off the energy L in the form of radiation, its mass diminishes by L/c².

in any case, is good to know the complete history/formula, and Sixty Symbols has a short video about this thing:

Math is Beautiful, math is the absolute truth and that makes it beautiful. Mathematicians even go so far as calling it an art form. 

mathematics, rightly viewed, possesses not only truth, but supreme beauty — a beauty cold and austere, like that of sculpture, without appeal to any part of our weaker nature, without the gorgeous trappings of painting or music, yet sublimely pure, and capable of a stern perfection such as only the greatest art can show - Bertrand Russel 

One of the most amazing equations, in my opinion, is the Lorentz factor, 

External image

Virtually all of the mathematics behind Einsteins theory or special relativity can be reduced back to this one, simple equation. basically, these few lines describe exactly what happens when you travel close to the speed of light, and the fact that it is as simple and short as it is, is beautiful.

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Look at Albert Einstein working in his Theory of General Relativity in Zurich:

Einstein’s search for general relativity spanned eight years, 1907-1915. Some periods were quiet and some were more intense. The moments when the great transition occurred, came sometime between the late summer of 1912, when Einstein moved from Prague to Zurich, and early 1913.

Source (and context): A Peek into Einstein’s Zurich Notebook, from the absolutely advisable page of Goodies by Professor John D. Norton, (Department of History and Philosophy of ScienceUniversity of Pittsburgh), from now in my bookmarks.