ASTRONOMY

ASTRONOMY. Colonial Americans lacked instruments and libraries. They had difficulty communicating with each other and often relied on English correspondents for news of other colonialists. During the seventeenth century, European astronomy was focused on extending Isaac Newton's mathematical description of the solar system, and a few Americans contributed their observations to the Royal Society of London. American observations served European theories.

When Venus passed in front of the sun in 1761 and 1769, transits revealed the distance of the earth from the sun. John Winthrop, professor of mathematics and natural philosophy at Harvard, organized an expedition to Newfoundland to observe the first transit. The Massachusetts Assembly assigned a ship to transport Winthrop's group and Harvard permitted him to take college instruments, provided they were insured against loss or damage. The observations were sent to Europe for analysis.

Winthrop lectured his students that determination of the distance of the earth from the sun would result in a deeper insight into God's wonderful works. Enlightenment faith in the discernable regularity of the universe also encouraged the study of astronomy in early American colleges. In its appeal to the Pennsylvania Assembly for funds to observe the 1769 transit, the American Philosophical Society, founded in Philadelphia in 1743, cited a more utilitarian goal, "the Promotion of Astronomy and Navigation, and consequently of Trade and Commerce." In a period of increasing cultural nationalism, the society also wanted to win recognition for American achievements.

Many of America's astronomers were surveyors. The self-taught American astronomer David Rittenhouse made his living as a clockmaker, but he was also a surveyor. In 1767, he constructed in Philadelphia his famous orrery, or mechanical planetarium, which represented with great precision the motions of the planets around the sun. The Pennsylvania assembly paid for it. The onset of the Revolutionary War suspended hope to build an observatory.

With political independence came a desire for cultural independence. However, little public patronage was forthcoming for astronomy in the early national period. In 1825, President John Quincy Adams pointed out that Europe had 130 "lighthouses of the skies" but the United States none. Yet his request for funds for a national observatory was denied.

The American Academy of Arts and Sciences, founded in Boston in 1780 by John Adams, published astronomical observations by Nathaniel Bowditch, a self-educated Salem seaman. His The New American Practical Navigator (1800) became the most widely used nautical guide, and in 1811, he observed a solar eclipse to improve the determination of the longitude of Cambridge. The European scientific community applauded Bowditch's translation and commentary on Pierre Laplace's Mécanique céleste. The American Academy offered to pay for publication, but Bowditch waited until he could afford to publish it himself.

Through much of the nineteenth century, the United States was a nation in development. While some of their European brethren made observations and contributed to the advance of knowledge, American astronomers often struggled with more mundane problems, including writing textbooks, acquiring books and journals for libraries, and building, equipping, and financing observatories. Elias Loomis, a professor at Western Reserve College in Ohio, at the University of the City of New York, and at Yale University, published An Introduction to Practical Astronomy in 1855 and a A Treatise on Astronomy in 1876, both of which went through numerous editions. At both New York and Yale, Loomis arranged to receive publications from European observatories on an exchange basis. His will left funds to pay observers and publish their results.

College observatories consisted of a small building and telescope intended for the education of undergraduate students, but they could not pay researchers or provide funds for publication. The University of North Carolina built an observatory in 1831, which lasted several years. Observatories were constructed at Yale (1830s), at Williams College (1838), at Western Reserve College (1838), at the Philadelphia High School (1838), at West Point (1839), and at Georgetown (1843). In 1839, Harvard lured William Cranch Bond from his private observatory to supply his own instruments and work for no salary. The great comet of 1843 aroused public interest, which manifested itself in public support to construct and endow the Harvard College Observatory. Harvard ordered from the German firm Merz and Mahler a twin to the Russian Pulkova Observatory's fifteen-inch (lens diameter) telescope, then the largest in the world.

There were also public observatories: the Cincinnati Observatory, whose cornerstone John Quincy Adams laid in 1843, and the Dudley Observatory in Albany, built between 1852–1856. The tribulations of the Cincinnati Observatory illustrate the obstacles to practicing astronomy in mid-nineteenth-century America. Ormsby MacKnight Mitchel, a West Point graduate, moved to Cincinnati and became professor of mathematics, civil engineering, mechanics, and machinery at Cincinnati College. His public lectures on astronomy led to the founding of the Cincinnati Astronomical Society and the municipal Cincinnati Observatory, funded by public subscription. After five hours of teaching, Mitchel would supervise construction of the observatory in the afternoons. Cincinnati purchased an 11.25-inch telescope from Merz and Mahler, but Mitchel spent much of his time displaying the heavens to subscribers, from 4:00 to 10:00 P.M. daily. He tried publishing a journal to raise money for auxiliary instruments and for his salary, the observatory having no endowment for operating expenses, and did make money from a book on popular astronomy and from surveying a railroad route. His observations of singular phenomena, a kind of natural history of the heavens, fell short of a new professional emphasis on measurement and theory, requiring considerable mathematical competence. Economic forces discouraged sustained, structured research.

A few would-be professional astronomers received training and employment with the Coast Survey, established in 1807 in response to commercial interests of seaboard states. In legislation for the Coast Survey in 1832, Congress explicitly declared that it did not authorize construction or maintenance of a permanent astronomical observatory. A decade later, the Naval Observatory was created surreptitiously, as part of the Depot of Charts and Instruments. Not until 1866, however, would the observatory begin a program of fundamental research in astronomy. Meanwhile, the Nautical Almanac, located in Cambridge, Massachusetts, was established under the Naval Observatory budget in 1849. It reported directly to the secretary of the navy, provided training and employment for a few astronomers, and improved navigation and raised America's scientific standing with an annual astronomical almanac more accurate and theoretically advanced than the British Nautical Almanac. Simon New-comb, one of America's best-known scientists at the end of the century, got his start at the Nautical Almanac, and also worked at the Naval Observatory. He analyzed the motions of the moon and planets.

There were also a few private observatories in America. Lewis Rutherfurd, a wealthy New Yorker and trustee of Columbia College, had a nine-inch diameter telescope, and also a small transit instrument belonging to Columbia College at his observatory at Second Avenue and Eleventh Street. The Coast Survey used this observatory in 1848 to determine the longitude of New York. Rutherfurd was a pioneer in astronomical photography. Not until late in the century, though, would individual American fortunes fund the establishment and sustenance of large observatories with systematic programs of scientific investigation carried on by full-time, paid employees.

The second half of the nineteenth century saw advances in telescope production, especially by the Boston firm of Alvan Clark & Sons. Their metal tubes were stiffer yet lighter than wooden telescopes. Larger pieces of optical glass were now available, and the Clarks figured the lens for the world's largest refracting telescope on five occasions: an 18.5-inch lens for the University of Mississippi in 1860, a 26-inch lens for the Naval Observatory in 1873 (with which Asaph Hall discovered Mars's moons in 1877), a 30-inch lens for the Pulkova Observatory in 1883, a 36-inch lens for the Lick Observatory of the University of California in 1887, and a 40-inch lens for the Yerkes Observatory of the University of Chicago in 1897. James Lick, a California land speculator during the gold rush, and Charles Yerkes, a Chicago street car magnate, put up the funds for their eponymous observatories, under university auspices, and Boston investor Percival Lowell directed his own observatory. All three observatories were far removed from cities, and Lick's and Lowell's were on mountain peaks. With the largest telescopes in the best locations, American observatories now surpassed all others.

Growing interest in astrophysics and in distant stars and nebulae encouraged the development of new observatories with large steerable reflecting (light focused by a curved mirror) telescopes suitable for photography and auxiliary instruments for the analysis of starlight. George Ellery Hale founded the Astrophysical Journal in 1895, the American Astronomical and Astrophysical Society in 1899, the Mount Wilson Observatory in 1904, and the International Astronomical Union in 1918. Hale was an early prototype of the high-pressure, heavy-hardware, big-spending, team-organized scientific entrepreneur. In 1902, Andrew Carnegie, rich from innovations in the American steel industry, created the Carnegie Institution of Washington to encourage investigation, research, and discovery in biology, astronomy, and the earth sciences. Its ten million dollars were more than the total of endowed funds for research in all American universities combined. Hale left the Yerkes Observatory to build, with Carnegie money, the Mount Wilson Observatory on a mountain above Los Angeles. There George Willis Ritchey, who accompanied Hale from Yerkes, made the photographic reflecting telescope the basic instrument of astronomical research, constructing a 60-inch telescope in 1908 and a 100-inch telescope in 1919. They were the largest telescopes in the world and revolutionized the study of astronomy. Harlow Shapley found that the system of stars is a hundred times larger than previous estimates and that the sun is far from the center. Edwin Hubble showed that spiral nebulae are independent island universes beyond our galaxy and that the universe is expanding. Cosmology, previously limited to philosophical speculations, joined mainstream astronomy.

The Mount Wilson Observatory depended on its relationship with physicists at the nearby California Institute of Technology for its dominance of astrophysics during the first half of the twentieth century. A scientific education was fast becoming necessary for professional astronomers, as astrophysics came to predominate, and the concerns of professionals and amateurs diverged. As late as the 1870s and 1880s, the self-educated American astronomer Edward Emerson Barnard, an observaholic with indefatigable energy and ocular acuteness, could earn positions at the Lick and Yerkes observatories with visual observations of planetary details and discoveries of comets and moons. Already, however, he was an exception and an anachronism. Soon an advanced academic degree and considerable theoretical understanding were required of professional astronomers in America.

Supposedly, only men could withstand the rigors of observing the heavens all night in unheated telescope domes. Women were first employed to examine photo-graphs of stellar spectra and to catalog the spectra. Edward Pickering, director of the Harvard College Observatory in 1881 and an advocate of advanced study for women, was so exasperated with his male assistant's inefficiency that he declared even his cook could do a better job of copying and computing. Pickering hired her and she did do a better job, as did some twenty more females over the next several decades, recruited for their steadiness, adaptability, acuteness of vision, and willingness to work for low wages. In 1925, Cecilia Payne, a graduate student, determined the relative abundances of eighteen chemical elements found in stellar atmospheres. Her Ph.D. thesis has been lauded as the most brilliant written in astronomy. Her degree, however, was from Radcliffe College, before Harvard granted degrees to women, and in subsequent employment at Harvard she was initially budgeted as "equipment."

Radio astronomy began in America in 1933. Karl Jansky, a radio engineer with the Bell Telephone Company, detected electrical emissions from the center of our galaxy while studying sources of radio noise. Optical astronomers were not interested, nor were Jansky's practical-minded supervisors. Grote Reber, an ardent radio amateur obsessed with distance communication, was interested, and built for a few thousand dollars a 31.4-foot-diameter pointable radio antenna in his backyard in Wheaton, Illinois. In 1940, he reported the intensity of radio sources at different positions in the sky. Fundamental knowledge underlying radio astronomy techniques increased during World War II, especially with research on radar.

Advances in nuclear physics during the war made possible quantitative calculations of the formation of elements in a supposed primeval fireball. The Russian-American physicist George Gamow sought to explain the cosmic abundance of elements as the result of thermo-nuclear reactions in an early hot phase of an expanding universe, consisting of high-energy radiation. In 1963, unaware of Gamow's work, Arno Penzias and Robert Wilson at the Bell Telephone Laboratories detected radiation of cosmic origin. Meanwhile, Robert Dicke at Princeton University had independently thought of the cosmic background radiation and set a colleague to work calculating its strength. When Dicke learned in 1965 of Penzias and Wilson's measurement, he correctly interpreted it as Gamow's predicted radiation. A Nobel Prize went to Penzias and Wilson. Their discovery won general acceptance of the big bang theory and refuted the rival steady state theory.

World War II changed the relationship between science and the state. Radar, missiles, and the atomic bomb established state-sponsored and state-directed research and development. Furthermore, groups of scientists brought together in wartime proved effective. After the war, engineers and physicists with their instruments, techniques, training, and ways of operating moved into astronomy. Then came Sputnik in 1957, the world's first satellite. This Soviet triumph challenged American supremacy in military might and world opinion.

After Sputnik, the National Science Foundation supplied many millions of dollars for construction of the Kitt Peak National Observatory on a mountain near Tucson, Arizona. It is the largest collection of big telescopes in the Northern Hemisphere. Seventeen universities came together in AURA, the Association of Universities for Re-search in Astronomy, to manage the observatory.

Another response to Sputnik was the creation of the National Aeronautics and Space Administration (NASA). Among its accomplishments are automated observatories launched into space, including the Hubble Space Telescope. Its primary mirror is eight feet in diameter. Including recording instruments and guidance system, the telescope weighs twelve tons. It has been called the eighth wonder of the world, and critics say it should be, given its cost of 1.5 billion dollars! The telescope is as much a political and managerial achievement as a technological one. Approval for a large space telescope was won in a political struggle lasting from 1974 to 1977, but not until 1990 were a plethora of problems finally overcome and the telescope launched into space, only to discover that an error had occurred in the shaping of the primary mirror. One newspaper reported "Pix Nixed as Hubble Sees Double." The addition of a corrective mirror solved the problem.

NASA also funds X-ray astronomy. Captured German rockets provided the first proof of X-rays from the sun. Astronomers did not expect to find X-ray sources and were skeptical that brief and expensive rocket-borne experiments were worthwhile. NASA, however, had more money than there were imaginative scientists to spend it, and the military, even more. One imaginative and eager scientist was the Italian-born Riccardo Giacconi, who in 1960, funded by the Air Force Cambridge Research Laboratories, discovered a cosmic X-ray source, and in 1963, detected a second. NASA adjudicates questions of scientific priority and supplies money for space observatories; industry helps build them; universities or consortiums of universities design and operate them and analyze the data. NASA then funded a rocket survey program and a small satellite for X-ray astronomy and in 1978 the Einstein X-ray telescope. Unlike the relatively quiescent universe seen by earth-bound astronomers, the universe revealed to engineers and physicists observing from satellites is violently energetic.

Major changes have occurred in both the size and scope of American astronomy over the centuries, but never more rapidly nor more dramatically than at the beginning of the Space Age. There were some five hundred American astronomers in 1962 and three times that many a decade later. Only four worked on X-rays in 1962 compared to over forty times that many in 1972. Over eighty percent of them were migrants from experimental physics, with expertise in designing and building instruments to detect high-energy particles.

Astronomers now realize that important cosmological features can be explained as consequences of new theories of particle physics, and particle physics increasingly drives cosmology. Conversely, particle physicists, having exhausted the limits of particle accelerators and public funding for yet larger instruments, turn to cosmology for information regarding the behavior of matter under extreme conditions, such as those prevailing in the early universe.

The spectacular rise of American astronomy roughly parallels the remarkable evolution of the nation, itself, from British colonies to world super power. Once limited to visual observations and determining positions, astronomy now includes cosmology, the study of the structure and evolution of the universe, and analysis of the physical and chemical composition of the universe and its components. Once peripheral, now American astronomers, men and women, formally educated in a variety of fields, working in large teams, on systematic long-term projects, and enjoying government patronage, lead world advances in instrumentation, observation, and theory.

ASTRONOMY

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