1958-

American Mathematician

Thomas C. Hales, a professor of mathematics at the University of Michigan, suddenly burst onto headlines around the world in the summer of 1998. The occasion was his proof of Kepler's sphere-packing conjecture, which had bedeviled mathematicians for some 400 years, and for which Hales offered a solution in more than 250 pages of proofs. A year later, he solved another nettlesome problem similar to the sphere-packing conjecture: the hexagonal honeycomb conjecture.

Hales was born in 1958, and became a professor of mathematics at the University of Michigan during the 1990s. He began working on the Kepler sphere-packing conjecture in 1988, 10 years before he offered his proof. Indeed, mathematicians had been studying the problem for four centuries.

The Kepler sphere-packing conjecture began with Sir Walter Raleigh (1554-1618), who asked his friend Thomas Harriot (1560-1621), a mathematician, for a simple formula to determine the number of cannonballs...