Daniel Kirkwood

Astronomer and mathematician, born in Harford, Maryland, USA. He became professor of mathematics at Delaware (1851) and at Indiana (1856). He explained the unequal distribution of asteroids in the asteroid belt as a result of the influence of Jupiter. These interruptions became known as Kirkwood gaps.

Born in Harford County, Maryland, he graduated in mathematics from the York County Academy in York, Pennsylvania in 1838. After teaching there for five years, he became Principal of the Lancaster High School in Lancaster, Pennsylvania, and after another five years he moved on to become Principal of the Pottsville Academy in Pottsville, Pennsylvania. In 1851 he became Professor of Mathematics at Delaware College and in 1856 Professor of Mathematics at Indiana University in Bloomington, Indiana, where he stayed till his retirement in 1886, with the exception of two years, 1865-1867, at Jefferson College in Canonsburg, Pennsylvania.

The most significant contribution of Daniel Kirkwood was his study in the orbits of the asteroids. In 1866 he published¹ the discovery of gaps in the distances of asteroids from the sun, named Kirkwood gaps in his honor.

Kirkwood also identified a pattern relating the distances of the planets to their rotation periods, which was called Kirkwood's Law. he was dubbed "the American Kepler" by Sears Cook Walker, who claimed that Kirkwood's Law proved the widely held Solar Nebula Theory.

In 1891, at age 77, he became a lecturer in astronomy at Stanford University. The asteroid 1951 AT was named 1578 Kirkwood in his honor and so was the lunar impact crater Kirkwood.

Kirkwood was probably a cousin of Iowa politician Samuel Jordan Kirkwood who became United States Secretary of the Interior under President James Garfield and President Chester A.