George E. Hale summary

External Websites
Below is the article summary. For the full article, see George Ellery Hale.

George E. Hale, (born June 29, 1868, Chicago, Ill.—died Feb. 21, 1938, Pasadena, Calif., U.S.), U.S. astronomer. He studied at Harvard and in Berlin. In 1888 he organized the Kenwood Observatory in Chicago. In 1892 he joined the faculty of the University of Chicago and began organizing the Yerkes Observatory, of which he was director until 1904. There he built the 40-in. (1-m) refracting telescope that remains the largest of its type in the world. He established the Astrophysical Journal in 1895. In 1904 he organized the Mount Wilson Observatory and was its director until 1923. There he built solar apparatus of great power as well as the huge 60-in. (1.5-m) and 100-in. (2.5-m) reflecting telescopes. In 1928 he began work on a 200-in. (5-m) reflecting telescope at Caltech’s Palomar Observatory. The telescope, which made its first observations in 1949, was named in his honour. As a researcher, Hale is known particularly for his discovery of magnetic fields in sunspots.

astronomy summary

External Websites

Learn about the history of astronomy and the significant contributions of Ptolemy, Nicolaus Copernicus, and Isaac Newton

Below is the article summary. For the full article, see astronomy.

astronomy, Science dealing with the origin, evolution, composition, distance, and motion of all bodies and scattered matter in the universe. The most ancient of the sciences, it has existed since the dawn of recorded civilization. Much of the earliest knowledge of celestial bodies is often credited to the Babylonians. The ancient Greeks introduced influential cosmological ideas, including theories about the Earth in relation to the rest of the universe. Ptolemy’s model of an Earth-centred universe (2nd century ad) influenced astronomical thought for over 1,300 years. In the 16th century, Nicolaus Copernicus assigned the central position to the Sun (see Copernican system), ushering in the age of modern astronomy. The 17th century saw several momentous developments: Johannes Kepler’s discovery of the principles of planetary motion, Galileo’s application of the telescope to astronomical observation, and Isaac Newton’s formulation of the laws of motion and gravitation. In the 19th century, spectroscopy and photography made it possible to study the physical properties of planets, stars, and nebulae, leading to the development of astrophysics. In 1927 Edwin Hubble discovered that the universe, hitherto thought static, was expanding (see expanding universe). In 1937 the first radio telescope was built. The first artificial satellite, Sputnik, was launched in 1957, inaugurating the age of space exploration; spacecraft that could escape Earth’s gravitational pull and return data about the solar system were launched beginning in 1959 (see Luna; Pioneer). See also big bang; cosmology; gamma-ray astronomy; infrared astronomy; radio and radar astronomy; ultraviolet astronomy; X-ray astronomy.