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Edwin Powell Hubble (November 20, 1889 – September 28, 1953) [1] was an American astronomer. He played a crucial role in establishing the fields of extragalactic astronomy and observational cosmology .
1923 – Edwin Hubble: Galaxies discovered; 1923 – Arthur Compton: Particle nature of photons confirmed by observation of photon momentum; 1924 – Bose–Einstein statistics; 1924 – Louis de Broglie: De Broglie wave; 1925 – Werner Heisenberg: Matrix mechanics; 1925–27 – Niels Bohr & Max Planck: Quantum mechanics
Later in the 1920s, Edwin Hubble showed that Andromeda was far outside the Milky Way by measuring Cepheid variable stars, proving that Curtis was correct. [6] It is now known that the Milky Way is only one of as many as an estimated 200 billion (2 × 10 11) [7] to 2 trillion (2 × 10 12) or more galaxies in the observable Universe.
November 23 – Edwin Hubble announces his discovery that Andromeda, previously believed to be a nebula, is actually another galaxy, and that the Milky Way is only one of many such galaxies in the universe. [1] The Einstein Tower near Potsdam, Germany, designed by Erich Mendelsohn, becomes operational as an astrophysical observatory.
Hubble's law can be easily depicted in a "Hubble diagram" in which the velocity (assumed approximately proportional to the redshift) of an object is plotted with respect to its distance from the observer. [30] A straight line of positive slope on this diagram is the visual depiction of Hubble's law.
The observational result of Hubble's law, the proportional relationship between distance and the speed with which a galaxy is moving away from us, usually referred to as redshift, is a product of the cosmic distance ladder. Edwin Hubble observed that fainter galaxies are more redshifted. Finding the value of the Hubble constant was the result ...
1923 – Edwin Hubble measures distances to a few nearby spiral nebulae (galaxies), the Andromeda Galaxy (M31), Triangulum Galaxy (M33), and NGC 6822. The distances place them far outside the Milky Way, and implies that fainter galaxies are much more distant, and the universe is composed of many thousands of galaxies.
1923 – Edwin Hubble resolves the Shapley–Curtis debate by finding Cepheids in the Andromeda Galaxy, definitively proving that there are other galaxies beyond the Milky Way. 1930 – Robert Trumpler uses open cluster observations to quantify the absorption of light by interstellar dust in the galactic plane ; this absorption had plagued ...