Astronomy

ASTRONOMY

Astronomical Leaps

In astronomy the greatest advance of the 1930s involved the discovery of the planet Pluto, the ninth and last in the solar system. The planet's existence was confirmed, almost by chance, on 18 February 1930 at the Lowell Observatory by Clyde William Tombaugh. Eight years later Seth Barnes Nicholson discovered the tenth and eleventh satellites of Jupiter. Solar research also advanced as astronomers learned, thanks to the advent of long-distance radio, the effects of solar activity on the earth's ionosphere. Such influence often caused static and blackout in communications. In 1932 an international network of solar observatories was created to ensure that the sun's activities could be observed around the clock. That same year the field of planetary physics also progressed when Walter Sydney Adams and Theodore Dunham Jr., both at the Mount Wilson Observatory, identified a thick layer of carbon dioxide as causing the absorption bands in the atmosphere of Venus.

New Answers and Questions about the Universe

In galactic astronomy Karl Jansky, a researcher at Bell Labs, discovered in 1931 a radio disturbance that became stronger every time he pointed a rotating antenna toward the center of the galaxy; unknowingly, he had noticed the radio emissions of the galaxy, a fact with important future consequences. Another fundamental step, this time in the field of stellar energy, was made in 1939 at Cornell University by German-born physicist Hans Bethe. He pointed out that stellar energy was in fact the result of nuclear fusion reactions, which formed a carbon-hydrogen cycle that later carried his name. His discovery made possible new advances in nuclear physics and posited a temperature of 18.5 million degrees Kelvin (approximately 333 million degrees Fahrenheit) at the center of the sun, a figure fairly close to British physicist Arthur Stanley Eddington's earlier prediction of 19 million degrees Kelvin (approximately 342 million degrees Fahrenheit). Bethe's theory also helped explain how stars enter phases in which they can maintain stationary states thanks to the carbon-hydrogen cycle.

NOBEL OR NOBLE PRIZE?

Established in 1929, the Noble Prize commemorates a nineteenth-century civil engineer, Alfred Noble (no relation to Alfred Nobel). Unlike the prestigious Swedish prize that usually acknowledges lifetime achievements, the five-hundred-dollar award requires that recipients be under thirty years old and present a paper for publication by one of the five main American engineering societies—the American Institute of Mining and Metallical Engineers, the American Society of Civil Engineers, the American Society of Mechanical Engineers, the American Institute of Electrical Engineers, or the Western Society of Engineers.

Source:

F. D. McHugh, "The Scientific American Digest," Scientific American, 148 (February 1933): 117.

Hubble's Legacy

Meanwhile, astronomer Edwin Powell Hubble proposed a constant to determine the age of the universe that gave a result of only two billion years. This contradicted what was already known about the age of the earth and other celestial objects. Subsequent measurements corrected the discrepancy, and Hubble's research was summarized in his 1936 book The Realm of the Nebulae, widely considered a milestone in the history of astronomy. His work opened the possibility of investigation into the nature of star clusters, especially with regard to their dynamics and mass. Similarly, research on stellar evolution brought about theories on the nature of neutron stars, believed to be composed of protons and electrons melted together. The nature of the interaction of subatomic particles, however, remained the chief concern of physics.

Sources:

Arthur Stanley Eddington, The Expanding Universe (Cambridge: Cambridge University Press, 1933);

Edwin Hubble, The Realm of the Nebulae (New Haven: Yale University Press, 1936).