Annus mirabilis papers

The annus mirabilis papers (from Latin annus mīrābilis, "miracle year") are the four papers that Albert Einstein published in Annalen der Physik (Annals of Physics), a scientific journal, in 1905. These four papers were major contributions to the foundation of modern physics. They revolutionized science's understanding of the fundamental concepts of space, time, mass, and energy. Because Einstein published all four of these papers in a single year, 1905 is called his annus mirabilis (miracle year). The first paper explained the photoelectric effect, which established the energy of the light quanta E = h f {\displaystyle E=hf} , and was the only specific discovery mentioned in the citation awarding Einstein the 1921 Nobel Prize in Physics. The second paper explained Brownian motion, which established the Einstein relation D = μ k B T {\displaystyle D=\mu \,k_{\text{B}}T} and led reluctant physicists to accept the existence of atoms. The third paper introduced Einstein's theory of special relativity, which used the universal constant speed of light c {\displaystyle c} to derive the Lorentz transformations. The fourth, a consequence of the theory of special relativity, developed the principle of mass–energy equivalence, expressed in the equation E = m c 2 {\displaystyle E=mc^{2}} and which led to the discovery and use of atomic energy decades later. These four papers, together with quantum mechanics and Einstein's later theory of general relativity, are the foundation of modern physics.