Happy Birthday to the father of quantum physics! Born Karl Ernst Ludwig Marx Planck, or Max, as he was known from age 10, was born on this day in 1858 in Kiel, Germany. He studied at the University of Munich before working as a professor of theoretical physics at the University of Kiel and the University of Berlin. He became close friends with Albert Einstein, with whom he played music often. Most physics students know Planck through the Planck’s constant, which is used to relate a photon’s energy to its wavelength. He’s easily one of the greatest scientific minds of the 20th century, and today we celebrate his birthday! Check out his biography at the Nobel Laureates website. His Wikipedia article is also notable.

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