HE DISCOVERED THE COMPOSITION OF THE SUN IS THE SAME AS THE EARTH AND DISCOVERED THE RELATIONSHIP BETWEEN A STARS TEMPERATURE AND ITS BRIGHTNESS AND HERE WRITES ABOUT THE EVOLUTION OF A STAR
HENRY NORRIS RUSSELL (1877-1957) SIGNED QUOTE, “Henry Norris Russell, Princeton, N. J., January 23, 1921”, on a card 4.5 x 3.5, by the American astronomer – one of the most influential during the first half of the 20th century – who played a major role in the establishment of modern theoretical astrophysics by making physics the core of astrophysical practice. He and Ejnar Hertzsprung independently discovered the relationship between the luminosity and surface temperature of stars that is summarized in what is now called the H-R diagram. He was an instructor and professor at Princeton University (1905-47) and was director of Princeton University Observatory (1912-47) where he measured and calculated the properties of stars. He co-wrote a two-volume textbook that became the standard astronomy textbook for about two decades. His handwritten quote, in full: “The enormous diameter of the red star Sepha Orionis, which results from Michelson’s recent measures, affords convincing evidence that this star is in an early stage of evolution.” He’s referring to Albert Abraham Michelson, the 1907 Noble Prize winning physicist. The card is in fine condition, with minor age toning.