Daniel Kirkwood was born on a farm in Hartford County, Maryland on September 27, 1814 and died in Riverside, California on June 11, 1895. He was teaching school at age 19, and learned algebra by studying a textbook with one of his pupils. He graduated from York County Academy, York, Pennsylvania in 1838 with a major in mathematics, and taught there for five years. 

He was Principal of the Lancaster High School, Lancaster, Pennsylvania from 1843 to 1848. During these years he published seven scholarly papers on astronomical topics in the Literary Record and Journal of the Linnaean Association of Pennsylvania College (now Gettysburg College). The second paper was The Asteroids, written after the discovery of the fifth asteroid, Astraea, on December 8, 1845. He left Lancaster to take a position as Principal of the Pottsville Academy, Pottsville, Pennsylvania. 

Kirkwood achieved instant international fame in August 1849 when his discovery of a mathematical analogy relating the rotations of the planets to their orbits was presented at the second meeting of the American Association for the Advancement of Science by the eminent astronomer Sears Cook Walker. David Brewster called it a “work of genius” in his 1850 Presidential Address to the British Association for the Advancement of Science. 

Kirkwood became Professor of Mathematics at Delaware College in 1851 and served as President from 1854 to 1856. He became Professor of Mathematics at Indiana University in 1856 and retired in 1886. In 1861 he suggested that meteor showers are the debris of disintegrated comets. The gaps in the distances of asteroids from the sun, announced in 1866, was his most important discovery. The are still called the “Kirkwood Gaps” in research papers a century after his death. 

Daniel Kirkwood’s bibliography lists 129 publications, including three books. Twenty-five of the papers and the third book were published after he retired in 1886. His last paper was published when he was 79, two years before he died. His memory is honored in Bloomington by Kirkwood Avenue (1885), Kirkwood Hall (1895) and Kirkwood Observatory (1900). The recent major endowment campaign of the Indiana University Foundation received a major gift that provided the endowment for a fully funded Daniel Kirkwood Professorship of Astronomy. Subsequently, an anonymous donor provided funds to double the endowment for the purpose of upgrading the Professorship to the Daniel Kirkwood Chair of Astronomy. More information on Daniel Kirkwood can be found in an article by Frank K. Edmondson that appeared in the Mercury, May/June 2000, Vol. 29, No. 3, pg. 26-33; published by the Astronomical Society of the Pacific. Indiana University Radio and Television Services produced a 25-minute video (In Memoriam - Daniel Kirkwood - 1814-1895) in 1995, the centennial of Kirkwood’s death. It was shown during the 1995 Mini University, and at meetings of the American Astronomical Society, the Lowell Observatory Advisory Board, and the Indiana Academy of Science.