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Edwin HubbleAmerican astronomer who proved that galaxies are made up of star systems
Date of Birth: 20.11.1889
Country:  USA |
Content:
Biography of Edwin Hubble
Edwin Powell Hubble was an American astronomer who proved that galaxies consist of stellar systems. Born on November 20, 1889, in Marshfield, Missouri, USA, he was the third child of a successful insurance agency owner. The Hubble family frequently changed their place of residence due to the father's fragile health. Despite having many servants at home, the children were taught to do household chores. During vacations, they were even allowed to work to earn pocket money. One memorable experience for Edwin was working as part of a surveying party that was mapping the route for a railroad in the forests around the Great Lakes. The incident where he was attacked by two bandits, but still emerged victorious despite being stabbed in the back, demonstrated his extraordinary physical strength and endurance. The Hubble family was religious, and their spiritual life was diverse. They frequently held home concerts, as everyone in the family played different instruments.
Edwin was an avid reader and had a particular interest in science fiction novels by Jules Verne. He developed an early fascination with astronomy. His sister, Helen Laine, recalled that this interest was influenced by their maternal grandfather, William Henderson James, who built a telescope that fascinated Edwin to the point where he requested to stay up late and observe through the instrument instead of celebrating his eighth birthday. His wish was granted. In 1906, Edwin Hubble graduated from high school and received a scholarship to study at the University of Chicago. He studied astronomy, mathematics, and physics. Among his athletic pursuits, Edwin particularly enjoyed football and boxing. He was so good at boxing that his coach offered him the opportunity to become a professional boxer. As one of the most promising students, he received a scholarship to continue his education in the United Kingdom. However, upon arriving there in the fall of 1910, Hubble decided not to specialize in astronomy and instead chose to study international law at the University of Oxford.
After obtaining a Bachelor of Laws degree, Hubble returned to America in the summer of 1913. However, his passion for astronomy drew him back, and he moved to Chicago, where he began working at the Yerkes Observatory. The observatory was established thanks to the donations of Chicago tram magnate Charles T. Yerkes, who wanted to immortalize his name. Yerkes' life was described by Theodore Dreiser in the novel "The Financier." The observatory, named after him, was equipped with state-of-the-art instruments for that time. It housed a 40-inch (100-centimeter) refracting telescope, the last great refractor in the world, and a 24-inch (60-centimeter) reflecting telescope. Hubble's first scientific work focused on studying the motions of stars. His doctoral dissertation was titled "Photographic Investigations of Faint Nebulae." Although around 20,000 nebulae had been discovered by that time, their nature remained unknown. Hubble discovered 512 new nebulae on large-scale photographs of the sky. His scientific research was interrupted by World War I. By that time, Hubble had received an invitation from George Ellery Hale, the director of the Mount Wilson Observatory, to join him and conduct observations with the largest telescope in the world at that time, a 100-inch reflecting telescope. To Hale's surprise, Hubble sent a telegram declining the offer, stating, "Regret cannot accept your offer. Am going to war."
In the officer training camp, Hubble was promoted to captain and appointed as the battalion commander of the "Black Hawks" division. In the fall of 1918, the division landed in France, but did not have a chance to participate in combat. After the war, Hubble returned to the United States as a major. After being demobilized, he moved to Pasadena and accepted Hale's offer to work at the Mount Wilson Observatory.
He joined the nebula photography group, which matched his scientific interests. Hubble observed extensively but published little. In his 1922 work, "A General Study of Diffuse Galactic Nebulae," he divided all nebulae into two types: galactic, associated with the Milky Way, and extragalactic, mostly visible away from it. In the early 1920s, Hubble investigated the mechanisms of emission from diffuse and planetary nebulae. He demonstrated that diffuse nebulae emit light reflected from nearby hot stars, while the emission from planetary nebulae is similar to fluorescence: intense ultraviolet radiation originates from a central star, which is then re-emitted by the nebula in the visible spectrum. Hubble also found a correlation between the brightness of reflecting nebulae and the luminosity of the illuminating stars.
Hubble's particular interest was the famous Andromeda Nebula (M31). He obtained a series of photographs of it using the 60-inch and 100-inch reflectors. On a plate taken on October 4, 1923, using the largest reflector, he discovered two new stars and one faint variable star within the nebula. Hubble had found this variable star on several dozen negatives obtained since the fall of 1909. After further observations and comparisons with earlier ones, it became clear that Hubble had discovered a typical Cepheid variable within the Andromeda Nebula. Astronomers are well aware that the apparent brightness of Cepheids can be used to determine their distance. However, if this Cepheid is part of the Andromeda Nebula, it becomes possible to determine the distance to the nebula itself. Hubble estimated its distance to be 1 million light-years (according to modern estimates, it is around 2 million light-years). Since this distance far exceeds the size of our own Galaxy, it was definitively proven that spiral nebulae are independent stellar systems located at vast distances from the Milky Way and resembling it. The concept of island universes received brilliant confirmation.
Hubble first presented his findings on January 1, 1925, at a meeting of the American Astronomical Society. For this research, he received the Association for the Advancement of Science Award, and his name first appeared in the "Who's Who in America" directory for 1924-1925.
Hubble continued his research on galaxies, studying their composition, structure, rotation, distribution in space, and motion. He proposed the first scientific classification of galaxies based on their shapes, which laid the foundation for the modern classification. Hubble divided all extragalactic nebulae into three types: elliptical (E), spiral (S), and irregular (Irr).
In nearby galaxies, Hubble discovered new stars, Cepheids, globular clusters, gas nebulae, red, and blue supergiants. He established a scale for extragalactic distances. Hubble developed a methodology for estimating distances to the most remote galaxies based on their brightness.
Hubble's scientific achievements were highly valued in scientific circles. In 1927, he was elected to the National Academy of Sciences in the United States, and the Royal Astronomical Society of the United Kingdom elected him as a Fellow.
Hubble was interested in the structure of the universe as a whole. In his 1926 paper, "Extragalactic Nebulae," he considered the possibility of a relativistic model of an expanding universe proposed by Dutch astronomer Willem de Sitter. However, not fully trusting theorists and theories, Hubble believed that only observations could lead to an understanding of the true nature of things. In expanding universe models, the velocity of galaxies' recession should be directly proportional to the distance between them. Hubble believed it was necessary to observe and confirm that the radial velocities increase with distance. He compiled a list of the faintest galaxies, which naturally were considered the most distant, and measured their radial velocities. For one very distant galaxy (NGC 7616), he obtained a radial velocity of 3779 km/s from the redshift of spectral lines. This significant value told Hubble much.
In March 1929, an article by Hubble titled "A Relation Between Distance and Radial Velocity Among Extra-Galactic Nebulae" was published in the Proceedings of the National Academy of Sciences. He gathered information on the radial velocities and distances of 46 nebulae. Based on the comparison of observational data, he concluded, "Distant galaxies are receding from us with a velocity proportional to their distance from us. The farther the galaxy, the greater its velocity."
v = Hr.
The coefficient of proportionality H in Hubble's law, where v is velocity and r is distance, was named the Hubble constant. He estimated its value to be 500 km/(s Mpc); according to modern estimates, Ho = 75 km/(s Mpc). This means that galaxies located 1 million parsecs away (3.26 million light-years) are "receding" from us at an average speed of 75 km/s, and those 100 times farther away are moving apart 100 times faster.
Hubble's discovery laid the foundation for the concept of an expanding universe. His name in the history of science stands alongside that of Nicolaus Copernicus. Both revolutionized our understanding of the universe.
In the early 1930s, Hubble gained worldwide recognition. In late 1930, his lecture was attended by Albert Einstein, who highly praised it. In the spring of 1934, Hubble delivered the Gaullaudet Lecture in Oxford and received an honorary doctorate from the University of Oxford. Based on his lecture series at Yale University, Hubble wrote the book "The Realm of the Nebulae," which was published in 1935. In the fall of 1936, he gave three lectures in Oxford under the title "An Observational Approach to Cosmology." The second edition of his book, with the same title, was published in 1937. In 1940, he received the Gold Medal of the Royal Astronomical Society.
Despite his high standing in American and global science, Hubble did not seek any honorary or administrative positions. Renowned astrophysicist Allan Sandage recalled, "He did all his work himself. He never had assistants right up to the end when illness struck him. He worked very hard, and his whole life was dedicated to his work."
In his personal life, Hubble was not as reserved as he was in his work. Among his friends were English writer Aldous Huxley, renowned Russian composer Igor Stravinsky, who emigrated from Russia after the Bolshevik Revolution, and Hollywood celebrities, including Walt Disney.
When World War II began, Hubble led the Southern California United Freedom Committee and called for immediate aid to the United Kingdom in October 1940. In his appeal, he said, "We all want peace, but it must be an honorable peace. Peace at any price is a religion of slaves... If there is a lesson that history has taught us, it is that strong people can determine their own destiny."
And, of course, Hubble did not limit himself to patriotic speeches. He was invited to the Army Ordnance Research Center in Aberdeen, where he worked on bomb tables for Russian bombs dropped by American aircraft. These bombs were used during the return flights of American "Flying Fortresses," which bombed targets in Germany's ally, Romania, and Hungary. Hubble recalled, "A real feat was the creation of bomb tables for Russian bombs, for which there were no aerodynamic data other than qualitative descriptions and shapes. These tables were used on our bombers when they turned back after landing on Russian territory."
Hubble's work was highly appreciated by the U.S. government, and he was awarded the Medal for Merit in 1946. The same medal was given to the scientists who led the development of atomic weapons in America.
In the post-war era, Hubble realized that human civilization could not survive another world war. In 1946, he spoke in Los Angeles with a speech titled "The War That Should Not Be." Hubble stated, "Even though it is against our desires, in order to survive, we must cooperate with each other. War or self-destruction - these concepts must be considered synonymous." He believed that humanity could only survive if it created a global government with a strong international police force.
Even after the war, scientific work remained the main focus for Hubble, and he immediately resumed his research upon returning to the observatory. He planned to compile an "Atlas of Galaxies." However, he did not have the opportunity to complete this work. He also did not have the chance to conduct a wide program of observations on the new 200-inch (5-meter) reflector telescope at the Palomar Observatory. This telescope was put into operation on January 26, 1949. Hubble took the first negative with the new telescope. But in July, he suffered a severe heart attack. His robust body seemed to overcome the illness, and he resumed his observations. Together with Sandage, he discovered a new type of variable star, later called Hubble-Sandage variables. They submitted their paper for publication in late June 1953, but it was published in November, after Edwin Hubble had already passed away. He died suddenly on September 28, 1953.
Alan Sandage remembered Hubble as follows: "Absolute force of spirit, moral fortitude, no rashness, a gentleman in appearance."
The largest space telescope, the Hubble Space Telescope, bears Edwin Hubble's name.
